Prefabricated cofferdam structure and construction method thereof

Abstract

The application discloses an assembled cofferdam structure and a construction method thereof, wherein the assembled cofferdam structure comprises a cofferdam main body, each side of the cofferdam main body is alternately connected by a first side cofferdam and a second side cofferdam, and the first side cofferdam and the second side cofferdam are detachably connected; and the plurality of sides of the cofferdam main body are sequentially connected in a head-to-tail mode through corner connecting assemblies. In the application, each side of the cofferdam main body is assembled and connected by the first side cofferdam and the second side cofferdam, which is convenient for transportation, can be driven into a bearing layer by means of a pile driver during construction, is simple and convenient for construction, reduces the amount of on-site construction, and improves construction efficiency; the first side cofferdam and the second side cofferdam both have a supporting pulling-out unit, which not only has a supporting effect to prevent deformation of a cofferdam plate, but also helps to pull out the side cofferdam, and the structure is ingenious.

Description

TECHNICAL FIELD

[0001] The present application relates to water conservancy, in particular to an assembled cofferdam structure, and to a construction method of the assembled cofferdam structure. BACKGROUND

[0002] In rural water conservancy irrigation projects, small bridges are often built for traffic use from the water power station on the river bank to the water channel in the farmland. When the bridge is built, a cofferdam usually needs to be built. Due to the small engineering and the limitation of the construction site, large mechanical equipment is difficult to enter the site when the cofferdam is built, and the construction is difficult. In addition, the cofferdams in these projects are generally welded, which has large engineering quantity and cannot be reused, thereby increasing the construction cost of the bridge; furthermore, the existing cofferdams also need to be additionally supported during construction to avoid buckling deformation of the cofferdam, which further increases the construction engineering quantity of the cofferdam structure, which is not conducive to the construction progress and engineering turnover of the small river bridge. Therefore, it is necessary to provide an assembled cofferdam which is simple to assemble and convenient to disassemble. SUMMARY

[0003] Therefore, the first object of the present application is to provide an assembled cofferdam structure. Another object of the present application is to provide a construction method of the assembled cofferdam structure.

[0004] To achieve the above-mentioned objects, the present application adopts the following technical solutions:

[0005] The assembled cofferdam structure comprises a cofferdam main body, each side of the cofferdam main body is connected alternately by a first side cofferdam and a second side cofferdam, and the first side cofferdam and the second side cofferdam are detachably connected; the plurality of sides of the cofferdam main body are connected in sequence by a corner connecting assembly;

[0006] The first side cofferdam comprises a first cofferdam plate, a first support pulling-out unit fixed to the first cofferdam plate, and a pair of first fixing units, the first fixing unit comprises a first fixing piece arranged vertically, a first bolt, and a first guide block, the first fixing piece is a slot structure with a side opening, the first guide block is arranged on the outer surface of the first side plate I of the first fixing piece, and the first bolt is arranged on the first side plate II of the first fixing piece;

[0007] The second side cofferdam comprises a second cofferdam plate, a second support pulling-out unit fixed to the second cofferdam plate, and a second fixing unit fixed to the second cofferdam plate at intervals, the second fixing unit comprises a second fixing piece arranged vertically and a second guide block arranged in the second fixing piece, and the second fixing piece is a slot structure;

[0008] The second side plate II of the second fixing member is inserted into the first fixing member and fixed on the first fixing member by the first bolt; the second guide block is arranged on the inner surface of the second side plate I of the second fixing member, and the first side plate I is inserted into the second fixing member and the first guide block and the second guide block are in sliding fit.

[0009] The first side cofferdam and the second side cofferdam are provided with a supporting pulling-out unit, which not only has a supporting effect to prevent deformation of the cofferdam, but also helps to pull out the side cofferdam, and the structure is ingenious.

[0010] Preferably, the corner connecting assembly comprises two vertically arranged third fixing units, the third fixing unit comprises a third fixing member in a groove structure, a third guide block arranged on the outer side surface of the third side plate I of the third fixing member, and a second bolt arranged on the third side plate II of the third fixing member.

[0011] The third side plate II of the third fixing member of the two third fixing units is connected vertically together, and the two first fixing members close to the corner are respectively inserted into the two third fixing members of the corner connecting assembly.

[0012] The corner connecting assembly has two third fixing members in two directions, which can connect the side cofferdams at the corner together, and then form a sealed cofferdam main body.

[0013] More preferably, the end of the first guide block has a first guide inclined surface, the end of the second guide block has a second guide inclined surface, and the end of the third guide block has a third guide inclined surface, the guide inclined surface has a guide effect, facilitating the assembly between the first side cofferdam and the second side cofferdam, and facilitating the assembly between the second side cofferdam and the corner connecting assembly, and improving the assembly efficiency.

[0014] More preferably, the bottom of the first fixing member, the bottom of the second fixing member, and the bottom of the third fixing member are provided with an insertion fixing member with a tapered tip, the upper part of the insertion fixing member is in a cylindrical structure and the lower part is in a conical structure, which facilitates the insertion of the first side cofferdam, the second side cofferdam and the corner connecting assembly into the bearing layer, and the construction is simple.

[0015] Preferably, the first fixing member and the first cofferdam, the second fixing member and the second cofferdam, and the first side plate I and the second side plate I are provided with a sealing gasket to ensure the sealing performance; the first bolt and the second bolt are provided with a buffer spring (preferably a compression spring).

[0016] Preferably, the first support pulling-out unit comprises at least two mountings fixed on the outer surface of the first coaming, support members fixed on the mountings, an operating member vertically arranged on the support members, and a pressing plate rotatably arranged at the bottom of the operating member; wherein the support members are horizontally arranged, each of the support members is fixed with at least two mountings, the operating member is threadedly connected with each of the support members, and the pressing plate is rotatably arranged at the bottom of the operating member.

[0017] The operating member of the present application is a vertical long screw rod, when the long screw rod is rotated, the pressing plate can be lifted or lowered along with the long screw rod, when the pressing plate is pressed on the bearing layer during the dismantling, a reverse force is provided, and then the inserting member is pulled out from the bearing layer, the quick dismantling of the side coaming and the corner connecting assembly is realized, and the pressing plate can be repeatedly used.

[0018] More preferably, the first support pulling-out unit further comprises at least two guide members vertically arranged through the support members and slidably connected with the support members, the bottom of the guide member is fixed on the pressing plate, the guide member has a guiding and limiting effect, and the twisting of the pressing plate is avoided; the upper part of the operating member is further provided with a rotating disc, and the operation is facilitated.

[0019] Preferably, the structure of the second support pulling-out unit is the same as that of the first support pulling-out unit.

[0020] The present application further provides a construction method of the assembled coaming structure, comprising the following steps:

[0021] Firstly, the first side coaming, the second side coaming and the corner connecting assembly are pre-prepared according to the design size;

[0022] Secondly, the first support pulling-out unit is installed on the outer side of the first coaming of each first side coaming, and the second support pulling-out unit is installed on the outer side of the second coaming of each second side coaming;

[0023] Thirdly, the three side edges of the coaming body are driven into the bearing layer by the piling equipment in the construction sequence from upstream to downstream, taking one of the side edges as an example: the inserting member of the first side coaming is inserted into the bearing layer, and the second side coaming is inserted into the bearing layer on both sides of the first side coaming;

[0024] Fourthly, the corner connecting assembly is inserted into each corner of the coaming body, and the last side edge of the coaming body is inserted into the bearing layer, so that the four side edges of the coaming body are folded.

[0025] In the fifth step, the first side cofferdam and the second side cofferdam are fixed together by the first bolt, and the second side cofferdam at the corner is fixed with the corner connecting assembly respectively by the second bolt.

[0026] Compared with the prior art, the present application has the following advantages:

[0027] In the present application, each side of the cofferdam body is assembled and connected by the first side cofferdam and the second side cofferdam, which is convenient for transportation and can be driven into the bearing layer by the pile driver during construction, thus simplifying the construction process, reducing the amount of on-site construction, and improving the construction efficiency. The first side cofferdam and the second side cofferdam both have a supporting and pulling-out unit, which not only has a supporting effect to prevent the deformation of the cofferdam, but also helps to pull out the side cofferdam, and the structure is ingenious. In addition, the cofferdam body of the present application is simple and convenient to assemble, and the side cofferdam and the corner connecting assembly can be pulled out by the reverse force provided by the supporting and pulling-out unit during disassembly, thus simplifying the disassembly process and enabling repeated use. Furthermore, each connecting node has a sealing gasket, which effectively ensures the sealing performance of the cofferdam body and prevents water leakage. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a structural schematic view (top view) of the present application.

[0029] Figure 2 is Figure 1 is an enlarged view (top view) of the first side cofferdam in the present application.

[0030] Figure 3 is Figure 1 is an enlarged view (top view) of the second side cofferdam in the present application.

[0031] Figure 4 is Figure 1 is an enlarged view of part A in the present application.

[0032] Figure 5 is Figure 1 is an enlarged view (top view) of the corner connecting assembly in the present application.

[0033] Figure 6 is Figure 1 is an enlarged view of part B in the present application.

[0034] Figure 7 is a front view of the first side cofferdam according to the present application. DETAILED DESCRIPTION

[0035] The embodiments of the present application will be described in detail below with reference to the accompanying drawings, which are implemented on the premise of the technical scheme of the present application, and give detailed implementation modes and specific operation processes, but the protection scope of the present application is not limited to the following embodiments.

[0036] It should be noted that in the description of the present application, the relational terms such as first and second and the like are used merely to differentiate one entity or action from another, without necessarily requiring or implying any actual such relationship or order between such entities or actions.

[0037] In the description of the present application, unless otherwise explicitly specified and limited, the terms "connected", "connected" that may appear should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0038] As shown in Figures 1-7 The present application provides an assembled cofferdam structure, which comprises a cofferdam body, each side of the cofferdam body is alternately connected by a first side cofferdam 1 and a second side cofferdam 2, the first side cofferdam 1 and the second side cofferdam 2 are detachably connected, and the cofferdam body is connected by a corner connecting assembly 3 between two adjacent sides. Wherein, the first side cofferdam 1 comprises a first cofferdam plate 1.1 arranged vertically, a first support pulling-out unit 1.2 fixed on the first cofferdam plate 1.1 and a pair of first fixing units arranged at intervals, the first support pulling-out unit 1.2 is arranged on the outer surface of the first cofferdam plate 1.1, and the two first fixing units are located on the inner surface of the first cofferdam plate 1.1; the first fixing unit comprises a first fixing piece arranged vertically, a first bolt 1.3 and a first guide block 1.4; wherein, the first fixing piece is a slot structure with side opening, and the first fixing piece is preferably a channel steel, denoted as first channel steel 1.5; the first side plate I of the first fixing piece is denoted as first flange 1.5I, and the second side plate II is denoted as first flange 1.5II. In actual installation, the first fixing unit is located on the inner side of the first cofferdam plate 1.1, and the first cofferdam plate 1.1 is fixed together with the web of each first channel steel 1.5 through the bolt, and the first channel steel 1.5 and the first cofferdam plate 1.1 have a first sealing gasket 1.6 therebetween, to ensure the sealing performance of the connecting joint;

[0039] The second side cofferdam 2 comprises a vertically arranged second cofferdam plate 2.1, a second support pulling-out unit 2.2 fixed on the second cofferdam plate 2.1, and a pair of spaced second fixing units, the second support pulling-out unit 2.2 and the two second fixing units are both fixed on the outer surface of the second cofferdam plate 2.1, and the second support pulling-out unit 2.2 is located between the two second fixing units. The second fixing unit comprises a second fixing piece in the form of a groove, preferably a second channel steel 2.3, and the second side plates I and II of the second fixing piece are respectively denoted as the second flanges 2.3I and 2.3II. In actual installation, the second channel steel 2.3 is installed at the end of the second cofferdam plate 2.1, the web of the second channel steel 2.3 is fixed on the second cofferdam plate 2.1 by bolts, and a second sealing gasket 2.4 is arranged between the second channel steel 2.3 and the second cofferdam plate 2.1 to ensure the sealing performance.

[0040] In combination Figures 2-4 It can be seen that the outer surface of the first flange 1.5I of the first channel steel 1.5 is provided with a first guide block 1.4 with a guide slope, the first flange 1.5II of the first channel steel 1.5 is provided with a first bolt 1.3, and the inner surface of the first flange 1.5I is provided with a mounting groove matched with the first bolt 1.3; the second fixing unit further comprises a second guide block 2.5 arranged on the second flange 2.3I, and the end of the second guide block 2.5 also has a guide slope. In actual assembly, the first channel steel 1.5 and the second channel steel 2.3 are arranged in opposite directions, the first flange 1.5I of the first channel steel 1.5 is inserted into the second channel steel 2.3, the second flange 2.3II of the second channel steel 2.3 is inserted into the first channel steel 1.5, the first bolt 1.3 fixes the second flange 2.3II on the first flange 1.5I of the first channel steel 1.5, and then the first side cofferdam 1 and the second side cofferdam 2 are fixed together.

[0041] In actual assembly, a sealing gasket can be pre-installed on the inner surface of the second flange 2.3II or the inner surface of the first flange 1.5I to ensure the sealing performance of the connection joint. Figure 4 It can be seen that the first bolt 1.3 is further provided with a first compression spring 1.7 (one end of which is fixed on the first bolt 1.3, and the other end of which has a stop block), so that the first flange 1.5II and the first flange 1.5I are always in a tightly connected state, further ensuring the sealing performance of the connection joint.

[0042] The side edges of the cofferdam body of the present application are assembled and connected by the first side cofferdam 1 and the second side cofferdam 2, which is convenient for transportation, can be driven into the bearing layer by means of a pile driver during construction, is simple and convenient to construct, reduces the amount of on-site construction, and improves the construction efficiency; the first side cofferdam 1 and the second side cofferdam 2 both have support pulling-out units, which not only have a supporting effect to prevent the cofferdam plate from deforming, but also help to pull out the side cofferdam, and the structure is ingenious.

[0043] In combination Figure 1 And Figures 5-6 It can be seen that the corner connecting assembly 3 comprises two vertically arranged third fixing units, each of which comprises a third fixing piece in the form of a channel structure, a third guide block 3.2 arranged on the outer side of the third side plate I of the third fixing piece, and a second bolt 3.3 arranged on the third side plate II of the third fixing piece; wherein the third fixing piece is preferably a channel steel, denoted as third channel steel 3.1, and the two side plates thereof are denoted as third flange 3.1I and third flange 3.1II respectively; the two third channel steels 3.1 of the corner connecting assembly 3 are perpendicular to each other and both point to the inner side of the cofferdam body, so as to connect the two second channel steels 2.3 at the corner together.

[0044] In combination Figures 5-6 It can be seen that the outer surface of the third flange 3.1I of each third channel steel 3.1 is provided with a third guide block 3.2 with a guide slope, the third flange 3.1II is provided with a second bolt 3.3, and the inner surface of the third flange 3.1I has a mounting groove matched with the second bolt 3.3. In actual installation, the third flange 3.1I of one of the third channel steels 3.1 can be inserted into one of the second channel steels 2.3 at the corner, and the second flange 2.3II of the second channel steel 2.3 is correspondingly inserted into the third channel steel 3.1; at the same time, the third flange 3.1I of the other third channel steel 3.1 is also correspondingly inserted into the other second channel steel 2.3 at the corner; finally, the second bolts 3.3 are fastened respectively, so that the two second channel steels 2.3 at the corner can be tightly connected together.

[0045] In actual installation, the first guide block 1.4 on each first channel steel 1.5, the second guide block 2.5 on each second channel steel 2.3, and the third guide block 3.2 on each third channel steel 3.1 can be installed in two or three vertically spaced apart, so as to ensure the guide insertion between the channel steels; in addition, each first channel steel 1.5 has two or more first bolts 1.3, and each third channel steel 3.1 has two or more second bolts 3.3, so as to ensure the reliability of the connecting joint. Furthermore, a second compression spring 3.4 can also be installed on each second bolt 3.3, which is used to press the second flange 2.3II of the second channel steel 2.3, so as to ensure the tight connection between the second flange 2.3II and the third flange 3.1I.

[0046] In actual production, the bottom of each first channel steel 1.5, the bottom of each second channel steel 2.3, and the bottom of each third channel steel 3.1 are all provided with an insertion fixing piece with a conical part, which is preferably an insertion column 5 with a cylindrical segment at the upper part and a conical structure at the lower part, as shown in Figure 7The first side cofferdam 1, the second side cofferdam 2 and the corner connecting assembly 3 are respectively driven into the bearing layer by means of a hammering device (such as a pile driver) during actual construction, thereby realizing the fixation of the cofferdam main body.

[0047] In combination Figure 2 and Figure 7 It can be seen that the first support pulling-out unit 1.2 comprises two mounting pieces fixed to the outer surface of the first coaming 1.1, a support piece (i.e. a support steel plate 1.2a) fixed to the mounting pieces, an operating piece penetrating through the support piece from top to bottom, and a pressing plate 1.2d rotatably arranged at the bottom of the operating piece; the mounting pieces are angle steels 1.2b vertically welded to the outer surface of the first coaming 1.1, and the wings of the two angle steels 1.2b are oppositely arranged; the support steel plate 1.2a is horizontally arranged and has two ends respectively welded to the two angle steels 1.2b, and the support steel plate 1.2a is transversely arranged to effectively support the first coaming 1.1 and avoid the bending deformation of the first coaming 1.1; the operating piece is an adjusting screw 1.2c threadedly connected with each support steel plate 1.2a from top to bottom, and the bottom of the adjusting screw 1.2c is connected with the pressing plate 1.2d through a bearing, so that the pressing plate 1.2d can be raised and lowered when the adjusting screw 1.2c is rotated, thereby realizing the adjustment of the position of the pressing plate 1.2d.

[0048] When the bridge pile foundation construction is completed, the cofferdam needs to be removed, at which time the adjusting screw 1.2c is rotated to lower the pressing plate 1.2d and press it on the bearing layer, and when the adjusting screw 1.2c is continuously rotated, the pressing plate 1.2d abuts against the bearing layer to provide a reverse force, and the reverse force gradually pulls out the two insertion columns 5 of the first side cofferdam 1 from the bearing layer, thereby realizing the rapid removal of the side cofferdam and the corner connecting assembly 3. The removed cofferdam main body can be used for the construction of the next bridge pile foundation, can be repeatedly used, and can reduce the construction cost.

[0049] In combination Figure 7 It can be seen that the first support pulling-out unit 1.2 further comprises two guide columns 1.2e, the guide columns 1.2e penetrate through the plurality of support steel plates 1.2a from top to bottom, and the guide columns 1.2e are in sliding cooperation with the support steel plates 1.2a, the bottom of the guide column 1.2e is fixed to the pressing plate 1.2d, has a guiding and limiting effect, and avoids the twisting of the pressing plate 1.2d during the lifting process. The top of the adjusting screw 1.2c is fixed with a turntable 1.2f, which can be used to rotate the adjusting screw 1.2c during actual removal, thereby facilitating the operation.

[0050] In the embodiment, each side of the cofferdam body comprises a first side cofferdam 1 and a second side cofferdam 2 arranged on both sides of the first side cofferdam 1, so that the two side cofferdams at each corner are both second side cofferdams 2, thereby unifying the structure of the corner connecting assembly 3 and facilitating on-site assembly. Of course, in other embodiments of the application, each side of the cofferdam body can also be formed by alternately connecting two first side cofferdams 1 and three second side cofferdams 2, or by assembling three first side cofferdams and four second side cofferdams.

[0051] The application also provides a construction method of the assembled cofferdam structure, comprising the following steps:

[0052] Firstly, position the line and drive the positioning pile at the construction site;

[0053] Secondly, manufacture the first side cofferdam 1, the second side cofferdam 2 and the corner connecting assembly 3 according to the positioning dimensions; wherein, a first channel steel 1.5 (with a plug column 5 at the bottom) is mounted on one surface of the first cofferdam 1.1, a first support pull-out unit 1.2 is welded between the two first channel steels 1.5, a first guide block 1.4 is welded on the outer surface of the first flange 1.5I of each first channel steel 1.5, and a first bolt 1.3 with a compression spring is threaded on the first flange 1.5II, thereby completing the manufacture of the first side cofferdam 1;

[0054] Similarly, a second channel steel 2.3 (with a plug column 5 at the bottom) is mounted on both ends of one surface of the second cofferdam 2.1, two second guide blocks 2.5 are welded on the inner surface of the second flange 2.3I of each second channel steel 2.3, a second support pull-out unit 2.2 is welded on the other surface of the second cofferdam 2.1, thereby completing the manufacture of the second side cofferdam 2;

[0055] The two third channel steels 3.1 (with a plug column 5 at the bottom) of the corner connecting assembly 3 are welded together, and two third guide blocks 3.2 are welded on the outer surface of the third flange 3.1I of each third channel steel 3.1, while two or more second bolts 3.3 are mounted on the other third flange 3.1II, thereby completing the manufacture of the corner connecting assembly 3;

[0056] Thirdly, use the pile driver to drive the three sides of the cofferdam body into the bearing layer in the construction sequence from upstream to downstream, taking one side as an example: firstly, insert the plug column 5 of the first side cofferdam 1 into the positioning pile, then use the pile driver to drive the plug column 5 into the bearing layer, then insert a second side cofferdam 2 on one side of the first side cofferdam 1 and drive it into the bearing layer; insert a second side cofferdam 2 on the other side of the first side cofferdam 1 and drive it into the bearing layer, thereby completing the driving operation of one side of the cofferdam body;

[0057] Fourth step, when the three side of the cofferdam body into the column 5 after the holding layer, in each corner into a corner connecting assembly 3, and with the help of pile driver into the holding layer; Then the last side of the cofferdam body into the holding layer, so that the four sides of the cofferdam body fold;

[0058] Fifth step, using the first bolt 1.3 and the second side cofferdam 2 are fixed together, using the second bolt 3.3 and the corner of the second side cofferdam 2 respectively with corner connecting assembly 3 fixed together.

[0059] When the assembled cofferdam construction is completed, the water in the cofferdam body is pumped out and excavated, and the cofferdam is set up while excavating; After excavation, the bridge pile foundation is constructed according to the conventional construction method. When the bridge pile foundation construction is completed, the first bolt 1.3 and the second bolt 3.3 are loosened, and the side cofferdam and the corner connecting assembly 3 are pulled out respectively. Among them, the first side cofferdam 1 is taken out as an example: the adjusting screw 1.2c is screwed to make the pressure plate 1.2d press on the upper surface of the holding layer, and then the adjusting screw 1.2c is continued to be screwed. At this time, the pressure plate 1.2d cannot go down under the resistance of the holding layer and provides a reverse force, thereby pulling out the first side cofferdam 1 from the holding layer, which is simple and convenient to disassemble. The assembled cofferdam of the application can be reused, reducing the cost of bridge construction.

[0060] Finally, it should be emphasized that the above only for the preferred embodiments of the present application, and not for the limitation of the present application, although the foregoing detailed description of the present application is made with reference to the foregoing embodiments, for those skilled in the art, it still can be modified without paying creative labor to the technical solutions recorded in the foregoing embodiments, or equivalent replacement of part of the technical features. Thus, any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A prefabricated cofferdam structure, comprising a cofferdam body, characterized in that: Each side of the main body of the cofferdam is formed by alternating connections of a first side cofferdam and a second side cofferdam, and the first side cofferdam and the second side cofferdam are detachably connected; multiple sides of the main body of the cofferdam are connected end to end by corner connecting components. The first side cofferdam includes a first cofferdam, a first support pull-out unit fixed to the first cofferdam, and a pair of first fixing units. The first fixing unit includes a vertically arranged first fixing member, a first bolt, and a first guide block. The first fixing member is a side-opening groove structure. The first guide block is disposed on the outer surface of the first side plate I of the first fixing member. The first bolt passes through the first side plate II of the first fixing member. The second side cofferdam includes a second cofferdam, a second support pull-out unit fixed to the second cofferdam, and a second fixing unit fixed to the second cofferdam at intervals. The second fixing unit includes a vertically arranged second fixing member and a second guide block arranged in the second fixing member. The second fixing member has a groove-shaped structure. The second side plate II of the second fixing member is inserted into the first fixing member and fixed to the first fixing member by the first bolt; the second guide block is disposed on the inner surface of the second side plate I of the second fixing member, the first side plate I is inserted into the second fixing member and the first guide block and the second guide block slide in cooperation. The corner connection assembly includes two vertically arranged third fixing units. Each third fixing unit includes a third fixing member with a groove-shaped structure, a third guide block disposed on the outer side of the third side plate I of the third fixing member, and a second bolt disposed on the third side plate II of the third fixing member. The third side plates II of the third fixing members of the two third fixing units are vertically connected together, and the two second fixing members near the corner are respectively inserted into the two third fixing members of the corner connection assembly.

2. The prefabricated cofferdam structure according to claim 1, characterized in that: The first guide block has a first guide slope at its end, the second guide block has a second guide slope at its end, and the third guide block has a third guide slope at its end.

3. The prefabricated cofferdam structure according to claim 1, characterized in that: The bottom of the first fixing member, the bottom of the second fixing member, and the bottom of the third fixing member are all provided with inserts with conical tips.

4. The prefabricated cofferdam structure according to claim 2, characterized in that: Sealing gaskets are provided between the first fixing member and the first enclosure plate, between the second fixing member and the second enclosure plate, and between the third side plate I and the second side plate II; buffer springs are provided on the first bolt and the second bolt.

5. The prefabricated cofferdam structure according to claim 1, characterized in that: The first support pull-out unit includes at least two mounting members fixed to the outer surface of the first enclosure, a support member fixed to the mounting members, an operating member passing through the support member from top to bottom, and a pressure plate rotatably disposed at the bottom of the operating member; wherein, the support member is horizontally disposed, each support member is fixedly connected to at least two mounting members, the operating member is threadedly engaged with each support member; and the pressure plate is rotatably disposed at the bottom of the operating member.

6. The prefabricated cofferdam structure according to claim 5, characterized in that: The first support pull-out unit also includes at least two guide members, which pass through multiple support members from top to bottom and slide with the support members. The bottom of the guide member is fixed to the pressure plate. The upper part of the operating member is also provided with a turntable.

7. The prefabricated cofferdam structure according to claim 5 or 6, characterized in that: The structure of the second support pull-out unit is the same as that of the first support pull-out unit.

8. A construction method for a prefabricated cofferdam structure as described in claim 1, characterized in that, Includes the following steps: The first step is to prefabricate the first side cofferdam, the second side cofferdam, and the corner connection components according to the design dimensions; The second step is to install a first support pull-out unit on the outer side of the first cofferdam of each first side cofferdam, and a second support pull-out unit on the outer side of the second cofferdam of each second side cofferdam. The third step is to use pile driving equipment to drive the three sides of the main body of the cofferdam into the bearing layer in the construction sequence from upstream to downstream. Taking one side as an example: first, insert the insert of the first side cofferdam into the bearing layer, and then insert a second side cofferdam into the bearing layer on both sides of the first side cofferdam. The fourth step is to install multiple corner connecting components at each corner of the main body of the cofferdam, and then install the last side of the main body of the cofferdam into the bearing layer, so that the four sides of the main body of the cofferdam are closed. The fifth step is to use the first bolt to fix the first side cofferdam and the second side cofferdam together, and use the second bolt to fix the second side cofferdam at the corner to the corner connection assembly respectively.

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