Flood control system construction and conversion construction method

Abstract

The invention relates to the field of flood control system construction and conversion construction methods, in particular to a flood control system construction and conversion construction method. The method comprises the following steps: filling a construction platform on the outer side of an existing flood bank, and constructing a temporary flood control device on the water side of an additional platform; the part, located on the immersed tube installation path, of an existing flood bank is broken, the revetment diaphragm wall is constructed through a construction machine, and the construction machine is located on the construction platform; according to the flood control system construction and conversion construction method, the risk of lateral collapse of an existing platform when a construction machine constructs the diaphragm wall in a dock entrance area is effectively reduced, more importantly, the flood control safety of the inner side of an embankment is effectively guaranteed, the construction period of foundation pit excavation is advanced, and more efficient construction is achieved.

Description

Technical Field

[0001] The invention relates to the field of flood control system construction and conversion construction methods, and in particular to a flood control system construction and conversion construction method. Background Art

[0002] At present, immersed tubes are increasingly used as municipal cross-river passages in inland river construction. For example, CN116277467A is a dry dock system and prefabrication method for prefabricated immersed tube tunnels. The immersed tubes are prefabricated by synchronous construction in different areas. After the immersed tubes are outfitted once, they are undocking by floating. The prefabrication period is short, the required site size is small, and it is not restricted by semi-submersible barges and docks. The prefabrication site size can be adjusted according to actual construction conditions. The land occupation is flexible, and both single and double docks can be set. It has good environmental adaptability and is particularly suitable for axis dry docks. There is no need to widen the axis site, which also reduces the difficulty of addressing temporary construction sites.

[0003] However, in the above process, since existing flood embankments are set on both sides of the existing river channel to avoid flood disasters caused by extreme water levels, the immersed tube segments need to be undocking after being prefabricated, which will inevitably involve breaking at least a part of the existing flood embankments, or the immersed tubes need to be connected to the opposite bank embankment, which will also involve breaking at least a part of the existing flood embankments on the opposite side, and further excavating downward to form the dock area of ​​the dry dock. Based on the general structure of the bank embankment (existing flood embankments are set on the existing platform, and the existing platform has not been reinforced with pile foundations and has not been sloped), the dock area cannot be excavated directly sometimes, and there will be a great risk of landslides. Therefore, the current conventional solution is to reinforce the surrounding area of ​​the dock area with ground-connected walls to ensure that there will be no landslides when the dock area is excavated.

[0004] Moreover, since the construction sites on both sides of the river in the city are very narrow and the dock area is very close to the river, when the ground-connected wall in the dock area is constructed by construction machinery, the existing platform is at great risk of lateral collapse.

[0005] Specifically preferably Figure 1 and 16 As shown, at least one side of the river channel 15 has an existing platform 30, and an existing flood embankment 1 is arranged on the upper part of the existing platform 30 for flood prevention. Generally, a foundation pit 7 is excavated on the shore side of the flood embankment 1 (the foundation pit 7 is used to form a dry dock 8, for example), and it is necessary to break the existing flood embankment 1 and at least a part of the existing platform 30 on the immersed tube installation path 16 to serve as a docking slot 50 for the immersed tube segment 12 to pass through or install the immersed tube segment 12. In order to ensure the safety of other facilities on the riverside and avoid flood prevention risks caused by breaking the existing flood embankment 1 and the existing platform 30, as shown in FIG. Figure 2As shown, it is necessary to install a water retaining and flood prevention structure 13 outside the foundation pit 7, and seal the two ends of the water retaining and flood prevention structure 13 with the existing undamaged flood embankment 1 and the existing platform 30 on the same side, and ground connecting walls need to be constructed at some locations to prevent landslides at some locations of the foundation pit 7.

[0006] However, since the foundation pit 7 is usually large, it takes a long time to construct the water retaining and flood control structure 13. At the same time, before the water retaining and flood control structure 13 is enclosed, the existing flood embankment 1 and the existing platform 30 that need to be removed cannot be removed, resulting in a delay in the construction of the ground-connected wall. The delay in the construction of the ground-connected wall will affect the excavation of the dock pit 50, and then affect the excavation of some positions in the dry dock 8, resulting in an impact on the early construction period. At the same time, the water retaining and flood control structure 13 encloses the entire foundation pit 7. At that time, the foundation pit 7 construction needs to open additional channels to allow equipment to enter and exit the construction area, which also affects the construction period. Summary of the invention

[0007] The purpose of the present invention is to overcome the problem that excavation construction in the dock area cannot be carried out before the construction of the foundation pit enclosed by the water retaining and flood control structure is completed in the background technology, and that the existing platform has a great risk of lateral collapse when the construction machinery is constructing the ground-connected wall around the dock area. A flood control system construction and conversion construction method is provided to overcome the risk of flood disasters caused by the destruction of flood control embankments during the construction stage of the immersed tube tunnel in the background technology, solve the construction safety of construction machinery on the existing platform, and ensure the flood control requirements of the immersed tube tunnel in different construction stages, so as to achieve more efficient construction.

[0008] In a first aspect, the present invention provides a flood control system construction and conversion construction method, comprising the following steps, based on an existing platform, an existing flood control embankment is set on the upper part of the existing platform:

[0009] S1: construct an additional platform on the water side of the existing platform, and construct a temporary flood control device between the existing platform and the additional platform, with both ends of the temporary flood control device being sealed and connected to the existing flood embankment;

[0010] S2: Destroy at least a portion of the existing flood embankment and the existing platform on the immersed tube installation path, and construct a revetment ground-connected wall flood control structure, both ends of which are sealed and connected to the existing flood embankment, wherein at least a portion of the revetment ground-connected wall flood control structure is constructed using construction machinery, at least a portion of the construction machinery is located on the existing platform, and the revetment ground-connected wall flood control structure is located on the shore side of the temporary flood control device;

[0011] Along the length direction of the existing flood embankment, the additional platform, the temporary flood control device and the revetment ground-connected wall flood control structure all pass through the immersed tube installation path.

[0012] The present application describes a method for construction and conversion of a flood control system, in which an additional platform is built outside an existing platform, and the additional platform applies lateral force to the existing platform to effectively reduce the risk of lateral collapse of the existing platform when construction machinery is constructing the ground-connected wall around the dock area. Furthermore, a temporary flood control device is constructed between the existing platform and the additional platform for temporary flood control during construction. The lateral pressure of the existing platform and the additional platform on the temporary flood control device effectively ensures the stability of the temporary flood control device after installation. Moreover, by utilizing the temporary flood control capacity of the temporary flood control device, at least a portion of the existing flood control embankment and the existing platform on the immersed tube installation path can be broken, so that the construction machinery can be used to construct the bank protection ground-connected wall flood control structure. By converting the temporary flood control device and the bank protection ground-connected wall flood control structure, the flood control capacity of the construction area is effectively guaranteed, and the flood control risk caused by the construction is effectively reduced.

[0013] Moreover, the flood control system construction and conversion construction method described in the present application greatly advances the construction time of the bank protection wall flood control structure and effectively advances the excavation period of the dock pit by 50% compared with the water retaining and flood control structure enclosure foundation pit construction plan. Moreover, temporary flood control devices can always be used throughout the construction process to compensate for the decrease in flood control capacity caused by the removal of at least a part of the existing flood control embankment and the existing platform located on the immersed tube installation path, thereby always ensuring the flood control capacity of the construction area and effectively reducing the flood control risks caused by construction.

[0014] To sum up, the flood control system construction and conversion construction method described in the present application not only effectively reduces the risk of lateral collapse of the existing platform when construction machinery is constructing ground-connected walls in the dock area, but more importantly, effectively ensures the flood control safety on the inner side of the embankment, advances the construction period of the foundation pit excavation, and achieves more efficient construction.

[0015] Preferably, the foundation pit comprises a connected docking groove pit and a dry dock, the dry dock is used for prefabricating immersed tube segments, and the docking groove pit can allow the immersed tube segments to pass through.

[0016] Preferably, the following steps are further provided after S3:

[0017] B1: constructing a water retaining and flood control structure outside the foundation pit, wherein the parts of the water retaining and flood control structure located on both sides of the foundation pit are sealed and connected to the existing flood embankment or the revetment ground-connected wall flood control structure;

[0018] B2: Break down the portion of the bank protection wall flood control structure located on the immersed tube installation path, and install the immersed tube section there;

[0019] B3: A temporary flood control structure is set up around the immersed tube segment, and the port of the immersed tube segment is sealed. Both sides of the temporary flood control structure are sealed and connected to the revetment ground-connected wall flood control structure. After the construction of the last immersed tube segment is completed, the water retaining flood control structure and the upright concrete wall are installed;

[0020] B4: Install a caisson at the location where the bank protection wall flood control structure is broken, and carry out the restoration of the existing flood embankment. The caisson is located outside the first immersed tube section to restore the existing flood embankment, and remove the part of the temporary flood control structure exposed on the ground.

[0021] After the installation of the immersed tube segment 12 is completed, the soil cannot be directly backfilled to realize the restoration construction of the original existing flood embankment, because backfilling the soil will involve the problem of scouring. Therefore, the caisson described in this application is located outside the first immersed tube segment to restore the existing flood embankment to prevent scouring. At the same time, the part of the temporary flood protection structure exposed to the ground is removed, and the part of the temporary flood protection structure located below the ground is left in place as a reinforced structure.

[0022] Preferably, the following steps are further provided after S3:

[0023] A1: A docking structure section is constructed in the foundation pit. The end of the docking structure section close to the river channel has an immersed tube section for docking with the immersed tube segment. The docking structure section is used as a transition section connecting the land road and the immersed tube segment.

[0024] A2: construct a temporary flood control structure outside the immersed tube section and seal the port of the immersed tube section. Both sides of the temporary flood control structure are sealed and connected to the revetment ground-connected wall flood control structure;

[0025] A3: The part of the revetment ground-connected wall flood control structure located on the immersed tube installation path is broken, and at this time, the part of the additional platform and the temporary flood control device located on the immersed tube installation path has also been broken;

[0026] A4: Install an immersed tube segment and seal the immersed tube segment with the immersed tube section;

[0027] A5: Restore the existing flood embankment on the outside of the immersed tube section and remove the exposed part of the temporary flood control structure.

[0028] Preferably, constructing a temporary flood control structure outside the immersed tube section specifically comprises the following steps:

[0029] A21: Install temporary flood control structures outside the immersed tube section;

[0030] A22: The space between the temporary flood control structure and the bank diaphragm wall flood control structure is filled with water, and backfilling is simultaneously performed on the backwater side of the temporary flood control structure.

[0031] Preferably, the space between the temporary flood control structure and the revetment ground-connected wall flood control structure is defined as the first space, and the space of the temporary flood control structure away from the revetment ground-connected wall flood control structure is defined as the second space;

[0032] Step A22 specifically includes the following steps:

[0033] A221. Fill the first space with water until the water filling height reaches a first height H1, and then perform backfilling in the second space until the contact height between the backfill and the temporary flood control structure reaches a second height H2, H2 = H1 ± 0.5m;

[0034] A222. Then, water is poured into the first space, and the water filling height is increased by a third height, and then backfilling is continued in the second space, and the contact height between the backfill and the temporary flood control structure is increased by a third height;

[0035] A223. Loop A222 until the contact height between the backfill soil and the temporary flood control structure reaches the target height.

[0036] Preferably, after S3, S4 is further provided: excavating a foundation trench in the river channel until the outside of the bank protection wall flood control structure, and breaking down the temporary flood control device and the portion of the additional platform located on the immersed tube installation path, the foundation trench being used for installing immersed tube sections.

[0037] Preferably, the top height of the additional platform is lower than the top height of the existing flood levee;

[0038] In S2, breaking down the portion of the existing flood embankment located on the immersed tube installation path specifically includes: excavating the existing flood embankment to be flush with the top of the additional platform.

[0039] The top height of the additional platform is lower than the top height of the existing flood embankment. Compared with the case where the top height of the additional platform is equal to or higher than the top height of the existing flood embankment, the water area occupied by the additional platform is reduced, and the construction cost of later dismantling of the additional platform is also effectively reduced.

[0040] Preferably, the top height of the temporary flood protection device is equal to or higher than the top height of the existing flood protection embankment.

[0041] When the top height of the additional platform is lower than the top height of the existing flood levee, in order to ensure the flood control effect in the area of ​​the existing flood levee to be destroyed, the top height of the temporary flood control device is constructed to be equal to or higher than the top height of the existing flood levee.

[0042] Preferably, the bank protection ground-connected wall flood-proof structure includes a ground-connected wall and a vertical concrete wall sealed to the upper part of the ground-connected wall, so that the bank protection ground-connected wall flood-proof structure and both ends of the vertical concrete wall are sealed to the existing flood embankment, the top height of the ground-connected wall is lower than the top height of the existing flood embankment, and the top height of the vertical concrete wall is equal to or greater than the top height of the existing flood embankment.

[0043] Preferably, the top of the ground-connected wall is integrally constructed with the upright concrete wall.

[0044] Preferably, the temporary flood protection device is a steel sheet pile.

[0045] Preferably, after the construction of the bank protection ground-connected wall flood control structure is completed, the temporary flood control device is dismantled on the shore using excavation machinery, thereby reducing the workload of foundation trench water construction and accelerating the progress of foundation trench forming.

[0046] Further preferably, after the construction of the ground-connected wall and the upper vertical concrete wall is completed, the temporary flood prevention device can be dismantled on the shore using an excavator, thereby reducing the workload of the foundation trench construction on water and accelerating the progress of the foundation trench forming.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] The flood control system construction and conversion construction method described in the present application not only effectively reduces the risk of lateral collapse of the existing platform when construction machinery is constructing a ground-connected wall in the dock area, but more importantly, effectively ensures the flood control safety on the inner side of the embankment, advances the construction period of the foundation pit excavation, and achieves more efficient construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 A schematic diagram of the construction steps for a flood control system construction and conversion construction method (confirmation of immersed tube installation path).

[0050] Figure 2 It is a schematic diagram of the construction steps of a flood control system construction and conversion construction method (construction construction platform and temporary flood control device).

[0051] Figure 3 A schematic diagram of the construction steps for the construction of a flood control system and a conversion construction method (partial removal of the existing flood control embankment).

[0052] Figure 4 A schematic diagram of the construction steps of a flood control system construction and conversion construction method (construction of revetment ground-connected wall).

[0053] Figure 5 A schematic diagram of the construction steps of a flood control system construction and conversion construction method (construction foundation trench).

[0054] Figure 6A schematic diagram of the construction steps for a flood control system construction and conversion construction method (construction of the foundation pit close to the dry dock side).

[0055] Figure 7 A schematic diagram of the construction steps for a flood control system construction and conversion construction method (caisson construction).

[0056] Figure 8 Schematic diagram of the construction steps for a flood control system construction and conversion construction method (restoration of flood control dikes).

[0057] Fig. 9 A schematic diagram of the construction steps of a flood control system construction and conversion construction method (construction docking structure section).

[0058] Fig.10 A schematic diagram of the construction steps for the construction of a flood control system and a conversion construction method (construction of a temporary flood control structure).

[0059] Fig.11 A schematic diagram of the construction steps for a flood control system construction and conversion construction method (installation of immersed tube segments).

[0060] Fig.12 This is a longitudinal schematic diagram of the temporary flood control structure.

[0061] Fig.13 Schematic diagram of the location of empty slots in a flood control system.

[0062] Fig.14 It is a schematic diagram of the structural longitudinal section of a flood control system.

[0063] Fig.15 This is a schematic diagram of the caisson installation location.

[0064] Fig.16 It is a basic layout diagram of the foundation pit for inland river immersed tube excavation in the background technology.

[0065] 1-existing flood embankment, 2-additional platform, 3-temporary flood control device, 4-bank protection ground-connected wall flood control structure, 5-vertical concrete wall, 6-foundation trench, 7-foundation pit, 8-dry dock, 9-immersed tube section, 10-temporary flood control structure, 11-first immersed tube section, 12-immersed tube section, 13-water retaining and flood control structure, 14-ground-connected wall, 15-river channel, 16-immersed tube installation path, 17-docking structure section, 18-tunnel section, 30-existing platform, 32-first slope structure, 33-empty trench, 34-soil structure, 35-reinforcement piles, 51-caisson, 55-restored flood embankment. DETAILED DESCRIPTION

[0066] The present invention is further described in detail below in conjunction with specific embodiments. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

[0067] Unless otherwise specified, in the description of the specific embodiments of the present invention, the terms indicating the orientation or position relationship such as "up", "down", "left", "right", "center", "inside", "outside", etc. are all based on the expression of the orientation or position relationship shown in the drawings, or are the orientation or position relationship when the invented product / equipment / device is usually used. These terms of orientation or position relationship are only for the convenience of describing the scheme of the present invention or simplifying the description in the specific embodiments, so as to facilitate the technicians to quickly understand the scheme, and do not indicate or imply that a specific device / component / element must have a specific orientation, or be constructed and operated in a specific position relationship, and therefore cannot be understood as a limitation on the present invention.

[0068] In addition, if the terms "horizontal", "vertical", "overhanging", "parallel" and the like appear, it does not mean that the corresponding devices / components / elements are required to be absolutely horizontal or vertical or overhanging or parallel, but may be slightly tilted or have deviations. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but may be slightly tilted. Alternatively, it can be simplified to mean that the corresponding devices / components / elements are set in directions such as "horizontal", "vertical", "overhanging", "parallel", etc., and can have an error / deviation of ±10% relative to the corresponding direction setting, more preferably an error / deviation within ±8%, more preferably an error / deviation within ±6%, more preferably an error / deviation within ±5%, and more preferably an error / deviation within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its role in the scheme of the present invention.

[0069] In addition, the expressions “first”, “second”, “third”, etc., which appear in the terms, are merely used to distinguish the description of the same or similar components and should not be understood as emphasizing or implying the relative importance of specific components.

[0070] In addition, in the description of the embodiments of the present invention, "several", "plurality" and "a number" represent at least 2. It can be any number such as 2, 3, 4, 5, 6, 7, 8, 9, and even more than 9.

[0071] In addition, in the description of the technical solution of the present invention, unless otherwise clearly specified / defined / restricted, the terms "set", "install", "connect", "connected", "provided with", "laid", and "arranged" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection, and can be welding, riveting, bolting, threading, and other commonly used connection means in the field. This connection can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection, or an indirect connection through an intermediate medium, and it can be the internal connection of two elements.

[0072] Example 1

[0073] like Figure 1-15 As shown, a flood control system construction and conversion construction method described in this embodiment includes the following steps:

[0074] S1: Building an additional platform 2 on the water side of the existing platform 30, and constructing a temporary flood prevention device 3 between the existing platform 30 and the additional platform 2, wherein both ends of the temporary flood prevention device 3 are sealedly connected to the existing flood embankment 1;

[0075] S2: Destroy at least a portion of the existing flood embankment 1 on the immersed tube installation path 16, and construct a revetment ground-connected wall flood-proof structure 4, both ends of which are sealed and connected to the existing flood embankment 1, wherein at least a portion of the revetment ground-connected wall flood-proof structure 4 is constructed using a construction machinery, at least a portion of which is located on the existing platform 30, and the revetment ground-connected wall flood-proof structure 4 is located on the shore side of the temporary flood protection device 3;

[0076] Along the length direction of the existing flood embankment 1 , the additional platform 2 , the temporary flood protection device 3 and the revetment ground-connected wall flood protection structure 4 all pass through the immersed tube installation path 16 .

[0077] The present application describes a method for construction and conversion of a flood control system, in which an additional platform 2 is built outside an existing platform 30, and the additional platform 2 applies lateral force to the existing platform 30, so as to effectively reduce the risk of lateral collapse of the existing platform when the construction machinery constructs the ground-connected wall around the dock area. Furthermore, a temporary flood control device 3 is constructed between the existing platform 30 and the additional platform 2 for temporary flood control during the construction process. The lateral pressure of the existing platform 30 and the additional platform 2 on the temporary flood control device 3 effectively ensures the stability of the temporary flood control device 3 after installation. Moreover, by utilizing the temporary flood control capacity of the temporary flood control device 3, at least a portion of the existing flood embankment 1 and the existing platform 30 located on the immersed tube installation path 16 can be broken, so that the construction machinery can construct the bank protection ground-connected wall flood control structure 4. By converting the temporary flood control device 3 and the bank protection ground-connected wall flood control structure 4, the flood control capacity of the construction area is effectively guaranteed, and the flood control risk caused by the construction is effectively reduced.

[0078] Moreover, the flood control system construction and conversion construction method described in the present application greatly advances the construction time of the bank protection wall flood control structure 4 and effectively advances the excavation period of the dock pit 50 compared to the water retaining and flood control structure enclosure foundation pit construction plan. Moreover, the temporary flood control device 3 can always be used throughout the construction process to compensate for the decrease in flood control capacity caused by the removal of at least a part of the existing flood embankment 1 and the existing platform 30 located on the immersed tube installation path 16, thereby always ensuring the flood control capacity of the construction area and effectively reducing the flood control risk caused by the construction.

[0079] To sum up, the flood control system construction and conversion construction method described in the present application not only effectively reduces the risk of lateral collapse of the existing platform when construction machinery is constructing the ground-connected wall around the dock area, but more importantly, it effectively advances the excavation period of the foundation pit 7 and achieves more efficient construction.

[0080] A preferred manner: in step S2, at least a portion of the existing flood embankment 1 and the existing platform 30 located on the immersed tube installation path 16 is broken.

[0081] A preferred solution: The subsequent construction on the dry dock side is as follows: the foundation pit 7 includes a connected docking slot 50 and a dry dock 8, the dry dock 8 is used to prefabricate immersed tube segments 12, and the docking slot 50 can allow the immersed tube segments 12 to pass through.

[0082] The water retaining and flood protection structure 13 is preferably a steel sheet pile.

[0083] The following steps are also set after S3:

[0084] B1: construct a water retaining and flood control structure 13 outside the foundation pit 7, and the parts of the water retaining and flood control structure 13 located on both sides of the foundation pit 7 are sealed and connected to the existing flood embankment 1 or the revetment ground-connected wall flood control structure 4;

[0085] B2: Breaking down the portion of the bank protection wall flood control structure 4 located on the immersed tube installation path 16, and installing the immersed tube segment 12 there;

[0086] B3: A temporary flood control structure 10 is arranged around the immersed tube segment 12, and the port of the immersed tube segment 12 is sealed. Both sides of the temporary flood control structure 10 are sealed and connected to the revetment ground-connected wall flood control structure 4. After the construction of the last immersed tube segment 12 is completed, a water retaining flood control structure 13 and a vertical concrete wall 5 are installed;

[0087] B4: Install a caisson 51 at the location where the bank protection wall flood control structure 4 is broken, and restore the existing flood control embankment 1. The caisson 51 is located outside the first immersed tube section 11 to restore the existing flood control embankment 1, and remove the part of the temporary flood control structure 10 exposed on the ground.

[0088] In the above scheme, after the structure of the caisson 51 is prefabricated, it is installed on site. If the on-site hoisting construction is not possible, a secondary platform can be formed at one side of the temporary flood control structure 10 for installing the caisson 51.

[0089] A preferred solution: The subsequent construction on the opposite bank away from the dry dock is as follows:

[0090] The following steps are also set after S3:

[0091] A1: A docking structure section 17 is constructed in the foundation pit 7. The end of the docking structure section 17 close to the river channel has an immersed tube section 9 for docking with the immersed tube segment 12. The docking structure section 17 is used as a transition section connecting the land road and the immersed tube segment 12. The docking structure section 17 includes the immersed tube section 9 and a tunnel section 18 connected to the land road. The immersed tube section 9 is closed at the top, and the tunnel section 18 is preferably open at the top.

[0092] A2: construct a temporary flood control structure 10 outside the immersed tube section 9, and seal the port of the immersed tube section 9, and both sides of the temporary flood control structure 10 are sealed and connected to the revetment ground-connected wall flood control structure 4;

[0093] A3: The part of the bank protection wall flood control structure 4 located on the immersed tube installation path 16 is broken, and at this time, the parts of the additional platform 2 and the temporary flood control device 3 located on the immersed tube installation path 16 are also broken;

[0094] A4: Install an immersed tube segment 12 and seal the immersed tube segment 12 with the immersed tube section 9;

[0095] A5: Restoration of the existing flood embankment 1 is carried out outside the immersed tube segment 12, and the exposed part of the temporary flood control structure 10 is removed.

[0096] Preferably, constructing the temporary flood control structure 10 outside the immersed tube section 9 specifically comprises the following steps:

[0097] A21: construct and install a temporary flood control structure 10 outside the immersed tube section 9;

[0098] A22: The space between the temporary flood control structure 10 and the bank protection wall flood control structure 4 is filled with water, and backfilling is performed on the backwater side of the temporary flood control structure 10 simultaneously.

[0099] Preferably, the space between the temporary flood protection structure 10 and the bank protection wall flood protection structure 4 is defined as the first space.

[0100] The space of the temporary flood control structure 10 away from the bank protection wall flood control structure 4 is defined as a second space;

[0101] Step A22 specifically includes the following steps:

[0102] A221. Fill the first space with water until the water filling height reaches the first height H1, and then perform backfilling in the second space until the contact height between the backfill and the temporary flood control structure 10 reaches the second height H2, H2 = H1 ± 0.5m;

[0103] A222. Then pour water into the first space, and increase the water filling height by a third height, and then continue backfilling in the second space, and increase the contact height between the backfill and the temporary flood control structure 10 by a third height;

[0104] A223. Loop A222 until the contact height between the backfill soil and the temporary flood control structure 10 reaches the target height.

[0105] Preferably, S4 is further provided after S3: excavating a foundation trench 6 in the river channel 15 until the outside of the bank protection wall flood control structure 4, and breaking down the temporary flood control device 3 and the portion of the additional platform 2 located on the immersed tube installation path 16, the foundation trench 6 being used to install the immersed tube segment 12.

[0106] Preferably, the top height of the additional platform 2 is lower than the top height of the existing flood embankment 1;

[0107] In S2 , the part of the existing flood embankment 1 located on the immersed tube installation path 16 is broken down specifically by excavating the existing flood embankment 1 until it is flush with the top of the additional platform 2 .

[0108] The top height of the additional platform 2 is lower than the top height of the existing flood embankment 1. Compared with the case where the top height of the additional platform 2 is equal to or higher than the top height of the existing flood embankment 1, the water area occupied by the additional platform 2 is reduced, and the construction cost of dismantling the additional platform 2 in the later stage is also effectively reduced.

[0109] Preferably, the top height of the temporary flood protection device 3 is equal to or higher than the top height of the existing flood protection embankment 1 .

[0110] When the top height of the additional platform 2 is lower than the top height of the existing flood embankment 1 , in order to ensure the flood control effect in the area of ​​the existing flood embankment 1 to be destroyed, the top height of the temporary flood control device 3 is constructed to be equal to or higher than the top height of the existing flood embankment 1 .

[0111] Preferably, the bank protection ground-connected wall flood-proof structure 4 includes a ground-connected wall 14 and a vertical concrete wall 5 sealed and connected to the upper part of the ground-connected wall 14, so that the bank protection ground-connected wall flood-proof structure 4 and both ends of the vertical concrete wall 5 are sealed and connected to the existing flood embankment 1, the top height of the ground-connected wall 14 is lower than the top height of the existing flood embankment 1, and the top height of the vertical concrete wall 5 is equal to or greater than the top height of the existing flood embankment 1.

[0112] Preferably, the top of the ground-connected wall 14 is integrally formed with the upright concrete wall 5 .

[0113] Preferably, the temporary flood protection device 3 is a steel sheet pile.

[0114] Preferably, after the construction of the bank protection wall flood prevention structure 4 is completed, the temporary flood prevention device 3 is removed on the shore using excavation machinery, thereby reducing the workload of the foundation trench 6 on water construction and accelerating the formation of the foundation trench 6.

[0115] Further preferably, after the construction of the ground-connected wall 14 and the upper upright concrete wall 5 is completed, the temporary flood prevention device 3 can be dismantled on the shore using an excavator, thereby reducing the workload of the foundation trench 6 on water construction and accelerating the formation of the foundation trench 6.

[0116] In the above scenario:

[0117] 1. First of all, the area to be destroyed of the existing flood control embankment 1 must be reinforced. The reinforcement boundary should be the same as the river bank. Direct reinforcement poses the risk of construction machinery falling into the river channel 15. Therefore, an additional platform 2 is filled in the river channel 15 as an additional platform 2 for construction machinery. The higher the height of the additional platform 2, the greater the slope of the additional platform 2 facing the water, and the more the filled soil will occupy the river channel, which will affect the width of the river channel and further affect the navigation of ships.

[0118] If the top of the additional platform 2 is made the same height as the top of the existing flood embankment 1, the water area occupied will increase under the same slope conditions. Therefore, the top of the additional platform 2 is usually made lower than the top of the existing flood embankment 1, and the existing flood embankment 1 is dug lower so that the top of the area to be destroyed in the existing flood embankment 1 is flush with the top of the additional platform 2 to facilitate construction machinery construction. However, this will affect flood control.

[0119] Filling the lowered additional platform 2 can reduce the water area occupied by the additional platform 2, and the amount of filled soil will also be less, because the filled additional platform 2 is only a temporary measure and will be demolished later, so less filled soil is also conducive to the later demolition work. Specifically, a low additional platform 2 is constructed and filled, and the original existing flood embankment 1 to be destroyed area is flattened, so that the top of the existing flood embankment 1 to be destroyed area is flush with the top of the additional platform 2.

[0120] 2. Steel sheet piles are driven on the river side of the additional platform 2, and the top of the steel sheet piles is at least 6m above the ground to ensure flood control. With this arrangement, the area to be destroyed in the existing flood embankment 1 can be excavated down to the same height as the additional platform 2, making it easier for construction machinery such as trenching machines and double-wheel milling machines to work on the additional platform 2, and the same is true for the other side of the river.

[0121] 3. When the revetment ground-connected wall flood control structure 4 is completed, there is no need to worry about the river bank collapsing. Then, the foundation trench 6 for the installation of immersed tubes can be dug. The part of the additional platform 2 located within the scope of the foundation trench 6 should also be dug, and the steel sheet piles within the scope of the foundation trench 6 will also be removed. The same is true for the other side of the river. Therefore, before digging the additional platform 2 and the part of the steel sheet piles located within the scope of the foundation trench 6, the revetment ground-connected wall flood control structure 4 that has just been completed is used to build a concrete wall along the river bank on the revetment ground-connected wall flood control structure 4, that is, a vertical concrete wall 5. The vertical concrete wall 5 is higher than the ground and is used for flood control. In this way, the immersed tube section 12 can be built normally in the dry dock 8, and the docking structure section 17 can also be built on the opposite side of the river. At this time, flood control uses the undamaged part of the existing flood embankment 1 + the revetment ground-connected wall flood control structure 4 and the upright concrete wall 5 thereon to block the river water. The tunnel behind the dry dock 8 can also be constructed at this time. When the construction of the immersed tube section 12 is completed, the onshore tunnel can also be completed, which can save construction time.

[0122] 4. After the immersed tube segment 12 is completed, the part of the revetment ground-connected wall flood-control structure 4 on the side of the dry dock 8 located on the immersed tube installation path 16 needs to be broken open again, and it is no longer possible to block water. Therefore, before breaking open the part, a water-retaining and flood-control structure 13 is erected on the outer side of the dry dock 8 to block water. The water-retaining and flood-control structure 13 is preferably made of steel sheet piles.

[0123] 5. After the immersed tube segment 12 is installed, the embankment needs to be restored to its original state, but the gap in the embankment is at least about 10m of the height of the immersed tube segment 12. Therefore, a wall will be set up after the immersed tube segment 12 is installed, that is, the temporary flood control structure 10, but the wall structure is relatively thin and needs to be further strengthened.

[0124] 6. A preferred method is to set up a second-phase platform near the bank protection wall flood control structure 4, use the second-phase platform to construct a caisson 51, and use the caisson 51 to seal the gap. After sealing, restore the existing flood control dike 1 on the top, and at the same time dig out all the remaining additional platforms 2 in the river. Another preferred method is not to fill the second-phase platform, and use a crane to construct and install the caisson 51 on the water, and use the caisson 51 to seal the gap. Therefore, there is no need for a second-phase platform, and the existing flood control dike 1 on the top can be directly restored after the caisson 51 is installed.

[0125] 7. When constructing an immersed tube tunnel in an inland river, both sides of the river are embankments. The embankments have flood control functions, but when constructing an immersed tube, the embankments at both ends will be temporarily demolished, which will affect flood control. This application mainly provides a flood control system construction and conversion construction method, and makes full use of existing structures to reduce the cost as much as possible and simplify the construction on the basis of ensuring effective flood control. Combining immersed tube prefabrication construction can achieve flood control and facilitate construction.

[0126] 8. The use of steel sheet piles in temporary flood control devices 3 can be recycled after construction, reduce costs, and achieve short-term use. The use of vertical concrete walls 5 can achieve long-term flood control, and the demolition stage is relatively easy, so it can be used in the medium term. The use of earth-filled embankments has a large amount of earth and stone, and the total length will be more stable. In addition, the use of earth-filled embankments can realize the arrangement of channels on the top of the embankment, which is conducive to ensuring the smooth passage during flood control.

[0127] 9. If steel sheet piles or concrete walls are used, the structure will be damaged immediately in the event of a traffic accident or abnormal collision, causing the flood control system to fail in a short period of time. In this case, the flood control system can be temporarily reinforced by temporarily filling sandbags on the river side, and restored in time on the side away from the river with the same structure. In this case, the top of the additional platform 2 preferably has a top surface filled with sandbags.

[0128] The construction of the embankment away from the dry dock 8 is similar to the above scheme, as follows:

[0129] 1. Build an additional platform 2 outside the existing flood embankment 1, construct a temporary flood prevention device 3 on the water side of the additional platform 2, and make both ends of the temporary flood prevention device 3 sealedly connected to the existing flood embankment 1;

[0130] 2. Excavate the existing flood embankment 1 until it is flush with the top of the additional platform 2, and construct a ground-connected wall 14 on the platform. After the construction of the ground-connected wall 14 is completed, build a vertical concrete wall 5 above the ground-connected wall 14; then remove the part of the temporary flood control device 3 located on the immersed tube installation path 16; and start excavating the foundation pit 7 on the shore side of the revetment ground-connected wall flood control structure 4, and construct the docking structure section 17. The end of the docking structure section 17 close to the river channel has an immersed tube section 9 for docking with the immersed tube segment 12. The construction process is to excavate after the surrounding ground-connected walls are completed, which is a conventional process. During this period of time, the dry dock and immersed tube prefabrication are being constructed on the north bank; after the construction of the docking point is completed, a temporary flood control structure is constructed here, similar to the position of the north bank in the lower right picture, and the front edge is broken to wait for the immersed tube installation.

[0131] 3. After the installation of the immersed tube segment 12 is completed, a second-stage platform is built, and the caisson 51 is constructed on the second-stage platform. Finally, the platform is dismantled, and the entire flood embankment is restored to its current structure; or the caisson is directly installed on the water without building a platform, and then the flood embankment is restored to its current structure.

[0132] 4. The existing flood embankment 1 is restored, and the upright concrete wall 5 is not demolished, but directly backfilled into the restored flood embankment 55 as a reinforcement structure. The existing flood embankment 1 is restored to its original state, and the exposed structure is demolished.

[0133] The above construction method will form a flood control system structure during the construction process, such as Figure 1-3 As shown, the present embodiment provides a flood control system structure, including an additional platform 2, the additional platform 2 including an existing platform 30 and the additional platform 2, a temporary flood control device 3 is arranged between the existing platform 30 and the additional platform 2, the additional platform 2 has a slope on the water side, the top of the temporary flood control device 3 extends out of the existing platform 30, the additional platform 2 includes a first stacking structure 32, the upper part of the first stacking structure 32 is filled with a soil structure 34, a second stacking structure 35 is arranged outside the soil structure 34, the outer side surface of the second stacking structure 35 forms a continuous slope with the outer side surface of the first stacking structure 32, and the first stacking structure 32 and the second stacking structure 35 are both made of sandbags.

[0134] The present invention provides a flood control system structure. A temporary flood control device 3 is arranged between the existing platform 30 and the additional platform 2 for temporary flood control needs. The first stacking structure 32 and the second stacking structure 35 are both made of sandbags, which can prevent scouring and avoid the soil structure 34 being washed away. It is also convenient for subsequent excavation, thereby reducing construction difficulty and construction cost.

[0135] Furthermore, the upper part of the first stacking structure 32 is filled with a soil structure 34, so that the additional platform 2 includes a soil structure 34, which is not entirely made of sandbags, further reducing the construction cost. On this basis, a second stacking structure 35 is arranged on the outside of the soil structure 34, and the outer side surface of the second stacking structure 35 forms a continuous slope with the outer side surface of the first stacking structure 32 to prevent the soil structure 34 from being washed away by river water, so that the soil structure 34 meets the use requirements.

[0136] In a preferred embodiment, the temporary flood control device 3 includes a steel sheet pile assembly, the top of which extends out of the existing platform 30, and the steel sheet pile assembly includes a plurality of steel sheet piles that are sealed and matched in sequence. The steel sheet piles can be recycled and reused after being dismantled later, further reducing the material cost of the construction.

[0137] In a preferred manner, the distance from the top of the first stacking structure 32 to the temporary flood protection device 3 is greater than the distance from the bottom of the first stacking structure 32 to the temporary flood protection device 3, so that an empty groove 33 is formed between the first stacking structure 32 and the temporary flood protection device 3, and a part of the soil structure 34 is filled in the empty groove 33.

[0138] To further reduce costs, an empty groove 33 is formed between the first stacking structure 32 and the temporary flood prevention device 3, and a part of the soil structure 34 is filled in the empty groove 33, which can prevent at least part of the soil structure 34 from being washed away by river water.

[0139] In a preferred manner, a support reinforcement structure 36 is provided on the existing platform 30 , and the support reinforcement structure 36 abuts against the portion of the steel sheet pile assembly extending out of the existing platform 30 .

[0140] In a preferred embodiment, the support reinforcement structure 36 is made of piled sandbags, which can be easily removed later.

[0141] In a preferred embodiment, reinforcement piles 37 are provided in the existing platform 30 .

[0142] In a preferred manner, at least part of the reinforcement piles 37 abut against the temporary flood protection device 3 .

[0143] In a preferred manner, the top of the reinforcement pile 37 against the temporary flood protection device 3 extends upwardly from the existing platform 30 .

[0144] In a preferred embodiment, a bank protection wall flood prevention structure 4 is provided on a side of the existing platform 30 away from the temporary flood prevention device 3 .

[0145] In a preferred embodiment, a vertical concrete wall 5 is provided on the top of the bank protection wall flood prevention structure 4 protruding upward.

[0146] In a preferred embodiment, the bank protection ground-connected wall flood control structure 4 includes vertical walls 41 arranged at intervals, the tops of adjacent vertical walls 41 are supported and connected with top plates 42, some of the reinforcement piles 37 support the top plates 42, and the reinforcement piles 37 are arranged on both sides of the vertical walls 41. When the bank protection ground-connected wall flood control structure 4 is constructed, a trench is first excavated using a construction machine, and then cast in the trench to form the bank protection ground-connected wall flood control structure 4, and the reinforcement piles 37 are arranged on both sides of the vertical walls 41 to prevent the hole collapse problem when the ground-connected wall is excavated.

[0147] A specific preferred solution: A flood control system structure described in this embodiment includes an existing platform 30 and an additional platform 2, a steel sheet pile assembly is arranged between the existing platform 30 and the additional platform 2, the top of the steel sheet pile assembly extends out of the existing platform 30, and the additional platform 2 includes a first stacking structure 32, the upper part of the first stacking structure 32 is filled with a soil structure 34, and a second stacking structure 35 is arranged on the side of the soil structure 34 away from the steel sheet pile assembly, and the outer side surface of the second stacking structure 35 forms a continuous slope with the outer side surface of the first stacking structure 32, and the first stacking structure 32 and the second stacking structure 35 are both made of sandbags. The top of the steel sheet pile assembly extends out of the existing platform 30, and the steel sheet pile assembly includes a plurality of steel sheet piles that are sealed and matched in sequence; the distance from the top of the first stacking structure 32 to the steel sheet pile assembly is greater than the distance from the bottom of the first stacking structure 32 to the steel sheet pile assembly, so that an empty groove 33 is formed between the first stacking structure 32 and the steel sheet pile assembly, and a part of the soil structure 34 is filled in the empty groove 33; a support reinforcement structure 36 is provided on the existing platform 30, and the support reinforcement structure 36 abuts against the part of the steel sheet pile assembly extending out of the existing platform 30, and the support reinforcement structure 36 is preferably formed by stacking sandbags. A reinforcement pile 37 is provided in the existing platform 30, and at least one of a mixing pile and a rotary jet pile. A bank protection ground-connected wall flood control structure 4 is provided on the side of the existing platform 30 away from the steel sheet pile assembly. A vertical concrete wall 5 is provided on the top of the bank protection ground-connected wall flood control structure 4 protruding upward.

[0148] There are several characteristics of the above flood control system architecture:

[0149] The first stacking structure 32 and the second stacking structure 35 are both made of sandbags, which can prevent scouring and prevent the soil structure 34 from being washed away, and are also convenient for later excavation. Although filling with stones can also prevent scouring, it is difficult to excavate. If it is not excavated cleanly, it will form a hard obstacle, which is not conducive to the safety of sailing.

[0150] The temporary flood prevention device 3 includes steel sheet piles. The steel sheet piles serve as flood prevention structures, which are convenient for later dismantling and recycling, thus saving construction costs.

[0151] The support reinforcement structure 36 is used for temporary support reinforcement to prevent the temporary flood prevention device 3 from tipping over to the existing platform 30 due to excessively high water levels in extreme cases.

[0152] The supporting reinforcement structure 36 is made of sandbags, which is convenient for later excavation.

[0153] Because part of the soil of the existing platform 30 is temporarily filled, and the ground-connected wall construction equipment is heavy, the equipment will be unstable if it goes up directly, so the existing platform 30 is reinforced with reinforcement piles 37, and the reinforcement piles 37 are preferably at least one of mixing piles and rotary jet piles. If the existing platform 30 is filled with stones, it will cause the revetment ground-connected wall flood control structure 4 to encounter stones when it is constructed into a groove, which greatly increases the difficulty of construction. At the same time, the reinforcement measures of the reinforcement piles 37 can further enhance the resistance of the temporary flood control device 3 and prevent the temporary flood control device 3 from tipping over.

[0154] Fill the additional platform 2 on the side of the existing platform 30, and construct a temporary flood prevention device 3, both ends of which are sealed and connected to the existing flood embankment 1;

[0155] Use construction machinery to construct at least part of the bank protection wall flood control structure 4 and remove part of the existing flood embankment 1. Because there is an additional platform 2, it is used to prevent the existing platform 30 from shifting and collapsing due to the deadweight of the construction machinery during construction.

[0156] Along the length direction of the existing flood embankment 1 , the additional platform 2 , the temporary flood protection device 3 and the revetment ground-connected wall flood protection structure 4 all pass through the immersed tube installation path 16 .

[0157] In a preferred embodiment, the top height of the additional platform 2 is lower than the top height of the existing flood embankment 1 ; then the existing flood embankment 1 can be excavated to be flush with the top of the additional platform 2 .

[0158] The top height of the additional platform 2 is lower than the top height of the existing flood embankment 1. Compared with the case where the top height of the additional platform 2 is equal to or higher than the top height of the existing flood embankment 1, the water area occupied by the additional platform 2 is reduced, and the construction cost of dismantling the additional platform 2 in the later stage is also effectively reduced.

[0159] In a preferred embodiment, the top height of the temporary flood protection device 3 is equal to or higher than the top height of the existing flood protection embankment 1 .

[0160] When the top height of the additional platform 2 is lower than the top height of the existing flood embankment 1 , in order to ensure the flood control effect in the area of ​​the existing flood embankment 1 to be destroyed, the top height of the temporary flood control device 3 is constructed to be equal to or higher than the top height of the existing flood embankment 1 .

[0161] In a preferred embodiment, the bank protection ground-connected wall flood-proof structure 4 includes a ground-connected wall 14 and a vertical concrete wall 5 sealed to the upper part of the ground-connected wall 14, so that the bank protection ground-connected wall flood-proof structure 4 and both ends of the vertical concrete wall 5 are sealed to the existing flood embankment 1, the top height of the ground-connected wall 14 is lower than the top height of the existing flood embankment 1, and the top height of the vertical concrete wall 5 is equal to or greater than the top height of the existing flood embankment 1.

[0162] In a preferred manner, the top of the ground-connected wall 14 is integrally constructed with the upright concrete wall 5 .

[0163] Traditional practices such as Figure 1 As shown, the water retaining and flood control structure 13 is directly enclosed outside the foundation pit 7 to make a large flood control system. With this flood control system, there is no need to convert various flood control structures. However, it takes a long time to construct the water retaining and flood control structure 13. Before the water retaining and flood control structure 13 is completed, the existing flood embankment 1 cannot be removed, resulting in a delay in the construction of the ground-connected wall 14. The delay in the construction of the ground-connected wall 14 will affect the excavation of the dry dock 8 and the dock entrance slot 50, thereby affecting the early construction period. At the same time, the flood control system encloses the dry dock 8 as a whole, and then the construction of the dry dock 8 requires the opening of a dedicated channel to allow equipment to enter the construction area of ​​the dry dock 8.

[0164] At the same time, the side of the dry dock 8 away from the dock entrance pit 50 was blocked by the water retaining and flood control structure 13 at the beginning of construction, resulting in no construction time for the land tunnel 52 in this area. Since the water retaining and flood control structure 13 is a temporary waterproof structure and has not been specially strengthened, it is impossible to excavate under the water retaining and flood control structure 13. The flood control system at the existing flood embankment 1 must be restored after the installation of the immersed tube segment 12 is completed before the water retaining and flood control structure 13 can be removed. After that, the overlapping area of ​​the land tunnel and the water retaining and flood control structure 13 can be constructed, and the construction period will be further extended. By adopting a flood control system construction and conversion construction method described in the present application, the prefabrication construction of the land tunnel and the immersed tube segment 12 can be carried out simultaneously, and the immersed tube segment 12 can be restored immediately after the installation is completed to achieve traffic.

[0165] In terms of safety, the water retaining and flood control structure 13 can ensure that the shore side of the water retaining and flood control structure 13 is not affected by floods, but the dry dock construction and immersed tube prefabrication stages are directly exposed to the flood range, which will have an adverse impact on the construction site. The flood control system construction and conversion construction method described in this application can not only protect the safety of the shore side of the water retaining and flood control structure 13, but also ensure the safety of the foundation pit 7 area.

[0166] In addition, after the installation of the immersed tube segment 12 is completed, the original flood embankment is not directly restored by backfilling, because the backfilling of soil will still involve the problem of scouring.

[0167] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A flood control system construction and conversion construction method, characterized in that: Based on the existing platform (30), an existing flood embankment (1) is arranged on the upper part of the existing platform (30), which includes the following steps: S1: constructing an additional platform (2) on the water side of the existing platform (30), and constructing a temporary flood prevention device (3) between the existing platform (30) and the additional platform (2), wherein both ends of the temporary flood prevention device (3) are sealedly connected to the existing flood embankment (1); S2: Destroy at least a portion of the existing flood embankment (1) located on the immersed tube installation path (16), and construct a revetment ground-connected wall flood control structure (4), wherein both ends of the revetment ground-connected wall flood control structure (4) are sealedly connected to the existing flood embankment (1), wherein at least a portion of the revetment ground-connected wall flood control structure (4) is constructed using construction machinery, at least a portion of the construction machinery is located on the existing platform (30), and the revetment ground-connected wall flood control structure (4) is located on the shore side of the temporary flood control device (3); S3: constructing a foundation pit (7) inside the bank protection wall flood control structure (4); Along the length direction of the existing flood embankment (1), the additional platform (2), the temporary flood prevention device (3) and the revetment ground-connected wall flood prevention structure (4) all pass through the immersed tube installation path (16).

2. A flood control system construction and conversion construction method according to claim 1, characterized in that: The foundation pit (7) comprises a dock opening groove pit (50) and a dry dock (8) which are connected to each other. The dry dock (8) is used to prefabricate immersed tube segments (12). The dock opening groove pit (50) is capable of allowing the immersed tube segments (12) to pass through. The following steps are also set after S3: B1: constructing a water retaining and flood prevention structure (13) outside the foundation pit (7), wherein the parts of the water retaining and flood prevention structure (13) located on both sides of the foundation pit (7) are sealed and connected to the existing flood embankment (1) or the revetment ground-connected wall flood prevention structure (4); B2: breaking down the portion of the bank protection wall flood control structure (4) located on the immersed tube installation path (16), and installing the immersed tube section (12) there; B3: a temporary flood prevention structure (10) is arranged on the periphery of the immersed tube segment (12), and the port of the immersed tube segment (12) is sealed, and both sides of the temporary flood prevention structure (10) are sealedly connected to the revetment ground-connected wall flood prevention structure (4), and the water retaining and flood prevention structure (13) is removed after the construction of the last immersed tube segment (12) is completed; B4: Install a caisson (51) at the location where the bank protection wall flood control structure (4) is broken, and carry out restoration construction of the existing flood control embankment (1), and dismantle the part of the temporary flood control structure (10) exposed on the ground.

3. A flood control system construction and conversion construction method according to claim 1, characterized in that: The following steps are also set after S3: A1: constructing a docking structure section (17) in the foundation pit (7), wherein the end of the docking structure section (17) close to the river channel has a immersed tube section (9) for docking with the immersed tube section (12), and the docking structure section (17) is used as a transition section connecting the land road and the immersed tube section (12); A2: constructing a temporary flood control structure (10) outside the immersed pipe section (9), and sealing the end of the immersed pipe section (9), wherein both sides of the temporary flood control structure (10) are sealedly connected to the revetment ground-connected wall flood control structure (4); A3: The portion of the bank protection wall flood control structure (4) located on the immersed tube installation path (16) is broken, and at this time, the portion of the additional platform (2) and the temporary flood control device (3) located on the immersed tube installation path (16) is also broken; A4: installing an immersed tube segment (12) and sealingly connecting the immersed tube segment (12) with the immersed tube section (9); A5: Restoration construction of the existing flood embankment (1) is carried out outside the immersed tube segment (12), and the exposed part of the temporary flood control structure (10) is removed.

4. A flood control system construction and conversion construction method according to claim 3, characterized in that: The construction of a temporary flood prevention structure (10) outside the immersed pipe section (9) specifically comprises the following steps: A21: construct and install a temporary flood control structure (10) outside the immersed tube section (9); A22: Water is poured into the space between the temporary flood control structure (10) and the bank protection wall flood control structure (4), and backfilling is simultaneously performed on the backwater side of the temporary flood control structure (10).

5. A flood control system construction and conversion construction method according to claim 4, characterized in that: The space between the temporary flood control structure (10) and the bank protection ground wall flood control structure (4) is defined as a first space, and the space on the side of the temporary flood control structure (10) away from the bank protection ground wall flood control structure (4) is defined as a second space; Step A22 specifically includes the following steps: A221. Fill the first space with water until the water filling height reaches a first height H1, and then perform backfilling in the second space until the contact height between the backfill and the temporary flood control structure (10) reaches a second height H2, H2 = H1 ± 0.5 m; A222. Then, water is poured into the first space, and the water filling height is increased by a third height, and then backfilling is continued in the second space, and the contact height between the backfill and the temporary flood control structure (10) is increased by a third height; A223. Loop A222 until the contact height between the backfill soil and the temporary flood control structure (10) reaches the target height.

6. A flood control system construction and conversion construction method according to claim 1, characterized in that: After S3, S4 is further provided: excavating a foundation trench (6) in the river channel (15) until the outside of the bank protection ground-connected wall flood control structure (4), and breaking down the temporary flood control device (3) and the portion of the additional platform (2) located on the immersed tube installation path (16), wherein the foundation trench (6) is used to install the immersed tube segment (12).

7. A flood control system construction and conversion construction method according to any one of claims 1 to 6, characterized in that: The top height of the additional platform (2) is lower than the top height of the existing flood embankment (1); In S2, the portion of the existing flood embankment (1) located on the immersed tube installation path (16) is broken down, specifically: the existing flood embankment (1) is excavated until it is flush with the top of the additional platform (2).

8. A flood control system construction and conversion construction method according to claim 7, characterized in that: The top height of the temporary flood protection device (3) is equal to or higher than the top height of the existing flood protection embankment (1).

9. A flood control system construction and conversion construction method according to any one of claims 1 to 6, characterized in that: The bank protection ground-connected wall flood control structure (4) comprises a ground-connected wall (14) and a vertical concrete wall (5) sealed to the upper part of the ground-connected wall (14), so that the two ends of the bank protection ground-connected wall flood control structure (4) and the vertical concrete wall (5) are sealed to the existing flood embankment (1), the top height of the ground-connected wall (14) is lower than the top height of the existing flood embankment (1), and the top height of the vertical concrete wall (5) is equal to or greater than the top height of the existing flood embankment (1); and / or, The temporary flood prevention device (3) is a steel sheet pile.

10. A flood control system construction and conversion construction method according to any one of claims 1 to 6, characterized in that: After the construction of the bank protection ground-connected wall flood prevention structure (4) is completed, the temporary flood prevention device (3) is removed on the shore using excavation machinery.

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