Composite cofferdam suitable for river channel construction

Abstract

The utility model discloses a composite cofferdam suitable for river channel construction, and relates to the technical field of hydraulic engineering construction. Comprising a soil bag temporary cofferdam and a rubble concrete cofferdam, the soil bag temporary cofferdam comprises W-shaped steel sheet piles, bagged clay arranged on the two sides of the W-shaped steel sheet piles and waterproof geotechnical cloth laid on the surfaces of the bagged clay, and clay is laid on the surface of the side, corresponding to the upstream face, of the waterproof geotechnical cloth; according to the soil bag temporary cofferdam, a water blocking structure can be rapidly formed, water flow in a construction area is prevented from permeating and scouring, a relatively dry and stable construction environment is provided, the construction quality and safety are guaranteed, the cofferdam can adapt to settlement changes of a foundation while the waterproof performance is kept, and the cofferdam is convenient to use. The waterproof structure effectively blocks permeation of water flow, the stability and durability of the cofferdam in a complex environment are ensured, the requirement for later maintenance is reduced, and the overall quality and safety of a project are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of water conservancy project construction, in particular to a composite cofferdam suitable for river channel construction. Background Art

[0002] River channel construction is a complex and important project. Especially when temporary water blocking or water flow control is required, the construction of cofferdams is particularly critical. As a temporary structure, the cofferdam not only needs to have good water blocking performance, but also needs to provide stable support during the construction process to ensure the safety of construction personnel and equipment. At present, the cofferdam construction methods mainly include earth embankment cofferdam, steel sheet pile cofferdam and concrete cofferdam. These traditional cofferdam construction methods have their own advantages and disadvantages in different environments and conditions.

[0003] Earthen embankment cofferdams are often used in shallow water areas or small projects, with the advantages of low cost and simple construction. However, earthen embankment cofferdams are susceptible to erosion and scouring by water flow, have poor stability and durability, and require frequent maintenance and reinforcement. Especially in high water levels or rapids, it is difficult to ensure the safety of earthen embankment cofferdams. Steel sheet pile cofferdams are widely used in deep water areas or large projects due to their good water-blocking properties and structural strength. Steel sheet pile cofferdams are fast to construct and can quickly form cofferdams and block water flow. However, the high cost of steel sheet piles and potential damage to riverbed structures increase environmental risks and construction costs. In addition, the long-term durability and anti-corrosion properties of steel sheet pile cofferdams still need to be improved in some special environments.

[0004] Existing cofferdam structures mostly have the disadvantages of poor engineering quality, poor waterproof performance, complex construction technology and high cost. In addition, since the cofferdam structure is located on the upper part of the riverbed, it is prone to uneven settlement, which may eventually cause the cofferdam to break or even overturn, affecting construction safety.

[0005] Chinese patent CN114235968 A discloses a steel sheet pile cofferdam suitable for thick silt layers and a construction method thereof. The utility model provides a steel sheet pile cofferdam suitable for thick silt layers, including steel sheet piles, purlins, tie rods, support rods, grille nets, steel pipe nets and fill; the steel sheet piles are arranged in two layers in parallel, the lower ends of the steel sheet piles extend into the foundation, and the inner and outer sides of each layer of steel sheet piles are provided with upper purlins and lower purlins. However, the utility model requires a combination of multiple structures such as multiple layers of steel sheet piles, purlins, tie rods, support rods, grille nets and steel pipe nets, and the construction process is complicated, which increases the construction difficulty and cost. Moreover, due to the use of two layers of parallel steel sheet piles and complex supporting structures, its flexibility is poor, and it is not easy to adapt to the cofferdam design with different shapes and sizes, which is not conducive to practical application on the construction site.

[0006] In order to overcome the defects of the existing cofferdam structure, the utility model proposes a stable, safe, efficient and economical composite cofferdam suitable for river channel construction and a construction method thereof. Utility Model Content

[0007] The purpose of the utility model is to provide a composite cofferdam suitable for river channel construction and a construction method thereof, so as to solve the problems raised in the above-mentioned background technology.

[0008] In order to solve the above technical problems, the utility model provides the following technical solutions: a composite cofferdam suitable for river channel construction, including a temporary earthbag cofferdam and a rubble concrete cofferdam, the temporary earthbag cofferdam includes W-shaped steel sheet piles, bagged clay arranged on both sides of the W-shaped steel sheet piles, and a waterproof geotextile laid on the surface of the bagged clay, and clay is laid on the surface of the waterproof geotextile corresponding to the water-facing side; the rubble concrete cofferdam is arranged on the side of the temporary earthbag cofferdam away from the water-facing side, the rubble concrete cofferdam includes a rubble concrete cofferdam body, a concrete cushion layer is arranged at the bottom of the rubble concrete cofferdam body, and a protrusion for connecting with the concrete cushion layer is arranged at the bottom of the rubble concrete cofferdam body.

[0009] According to the above technical solution, a left interlocking plate and a right interlocking plate are respectively arranged on both sides of the W-shaped steel sheet pile, and rod insertion holes are respectively arranged on the left interlocking plate and the right interlocking plate. There are multiple W-shaped steel sheet piles, and the W-shaped steel sheet piles are connected end to end. The rod insertion holes of the left interlocking plate and the right interlocking plate of adjacent W-shaped steel sheet piles are opposite to each other, and rods are arranged in the rod insertion holes.

[0010] According to the above technical solution, water-stop steel plates are fixedly connected between adjacent W-shaped steel sheet piles.

[0011] According to the above technical solution, the bagged clay is composed of an outer snakeskin woven bag and an inner toughness waterproof plastic bag, and clay is contained in the inner bag.

[0012] According to the above technical solution, a rubber waterstop is provided on the water-facing surface of the rubble concrete cofferdam body, and the rubber waterstop is fixedly connected to the rubble concrete cofferdam body through fixing bolts. Slopes formed by bagged clay are provided on both sides of the rubble concrete cofferdam body, and felt layers are provided inside the slopes.

[0013] According to the above technical solution, the felt layer on the side close to the water surface is inclined, and the felt layer on the side away from the water surface is vertically arranged.

[0014] According to the above technical solution, a plastic steel grille is provided on the slope surface on one side close to the water-facing surface, and the plastic steel grille is fixedly connected to the rubble concrete cofferdam body through a tie rod.

[0015] According to the above technical solution, the tie rod includes a rod body, one end of which is connected to an anchor head via an upper pull ring and a lower pull ring, a pad is fixedly connected to the anchor head, the anchor head is fixed inside the rubble concrete cofferdam body, the rod body is fixedly connected to bolts passing through holes in bagged clay and plastic steel grating, and a gasket is provided between the bolts and the plastic steel grating.

[0016] According to the above technical solution, the rubble stone concrete cofferdam body is arranged in sections, and construction joints are arranged between adjacent rubble stone concrete cofferdam bodies, and adjacent rubble stone concrete cofferdam bodies are connected by connecting steel plates.

[0017] According to the above technical solution, the connecting steel plate includes a T-shaped steel plate fixed inside the rubble concrete cofferdam body, a U-shaped steel plate is provided on the side of the T-shaped steel plate away from the corresponding rubble concrete cofferdam body, and the U-shaped steel plates of adjacent connecting steel plates are interlocked.

[0018] Compared with the prior art, the beneficial effects achieved by the utility model are:

[0019] (1) The utility model combines earthbag temporary cofferdam with rough stone concrete cofferdam. First, earthbag temporary cofferdam is constructed to ensure a good working environment when constructing rough stone concrete cofferdam. Earthbag temporary cofferdam can quickly form a water-blocking structure to prevent water infiltration and scouring in the construction area, provide a relatively dry and stable construction environment, and ensure the quality and safety of construction. In addition, this combined design facilitates the maintenance of the cofferdam and ensures waterproof performance during construction.

[0020] (2) The W-shaped steel sheet pile structure adopts a splicing method to adapt to cofferdams of different shapes and is easy to construct and dismantle. The steel sheet pile is made of Q345B steel and is formed by hot rolling. It has excellent mechanical properties and corrosion resistance. This splicing design not only improves the flexibility of construction, but also simplifies the construction process, allowing temporary cofferdams to be quickly built and dismantled. It is suitable for various complex river environments and improves construction efficiency.

[0021] (3) The rubble concrete cofferdam is equipped with settlement joints every 15 meters, which can effectively deal with the problem of uneven settlement of the cofferdam caused by the silt in the riverbed. By reasonably setting the settlement joint structure, the cofferdam can adapt to the settlement changes of the foundation while maintaining its waterproof performance, avoiding damage to the integrity of the cofferdam. This design not only enhances the stability of the cofferdam, but also extends its service life, ensuring the safety and reliability of construction.

[0022] (4) The utility model adopts a variety of combined waterproof structures, which significantly improves the waterproof performance of the cofferdam. The rough stone concrete cofferdam is built with multiple layers of waterproof materials such as rubber water stop, felt layer and waterproof geotextile to form a multi-layer waterproof barrier. These waterproof structures effectively block the penetration of water flow, ensure the stability and durability of the cofferdam in complex environments, reduce the need for later maintenance, and improve the overall quality and safety of the project. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0024] Figure 1 It is a main structural schematic diagram of the utility model;

[0025] Figure 2 It is a schematic diagram of the W-shaped steel sheet pile structure of the utility model;

[0026] Figure 3 This is a schematic diagram of the bagged clay structure of the utility model;

[0027] Figure 4 It is a schematic diagram of the construction process of the rough stone concrete cofferdam body of the utility model;

[0028] Figure 5 It is a schematic diagram of the tie rod structure of the utility model;

[0029] Figure 6 It is a schematic diagram of the structure of the rough stone concrete cofferdam body and the connecting steel plate of the utility model;

[0030] Figure 7 It is a schematic diagram of the structure of the connecting steel plate of the utility model;

[0031] In the figure: 1-W-type steel sheet pile, 1-1-right interlocking plate, 1-2-left interlocking plate, 1-3-rod hole, 1-4-rod, 1-5-waterstop steel plate, 2-bags of clay, 2-1-snake skin woven bag, 2-2-tough waterproof plastic bag, 3-waterproof geotextile, 4-clay, 5-concrete cushion, 6-rubber concrete cofferdam body, 7-rubber waterstop, 8-felt layer, 9-plastic steel grille, 10-tie rod, 10-1-rod body, 10-2-gasket, 10-3-bolt, 10-4-upper pull ring, 10-5-lower pull ring, 10-6-pad, 10-7-anchor head, 11-joint stone, 12-tie bar, 13-fixing bolt, 14-construction joint, 15-connecting steel plate, 15-1-U-type steel plate, 15-2-T-type steel plate. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0033] See also Figure 1-7 The utility model provides a technical solution: a composite cofferdam suitable for river channel construction, including a temporary earthbag cofferdam and a rough stone concrete cofferdam, the temporary earthbag cofferdam includes a W-shaped steel sheet pile 1, bagged clay 2 arranged on both sides of the W-shaped steel sheet pile 1, and a waterproof geotextile 3 laid on the surface of the bagged clay 2, and the waterproof geotextile 3 is laid on the surface of the side of the water-facing surface corresponding to the waterproof geotextile 3. The temporary earthbag cofferdam is used to block the water flow of the river channel to facilitate subsequent construction, and the waterproof geotextile 3 adopts a high-molecular flexible geotextile made of polyvinyl chloride and polyethylene;

[0034] The rubble stone concrete cofferdam is arranged on the side of the earthbag temporary cofferdam away from the water-facing surface, and the rubble stone concrete cofferdam comprises a rubble stone concrete cofferdam body 6, a concrete cushion layer 5 is arranged at the bottom of the rubble stone concrete cofferdam body 6, and a protrusion for connecting with the concrete cushion layer 5 is arranged at the bottom of the rubble stone concrete cofferdam body 6, the rubble stone concrete cofferdam body 6 is a gravity cofferdam, cast with C20 concrete and rubble stone blocks, and the amount of rubble stone blocks is controlled not to exceed 25% of the volume of the gravity cofferdam; a protrusion is arranged at the bottom of the rubble stone concrete cofferdam body 6, the slope of the protrusion is 1:0.5, and the height of the protrusion is greater than 200mm; the protrusion of the rubble stone concrete cofferdam body 6 is inserted into the C30 concrete cushion layer 5;

[0035] Specifically, the left interlocking plate 1-2 and the right interlocking plate 1-1 are respectively arranged on both sides of the W-shaped steel sheet pile 1, and the W-shaped steel sheet pile 1 is formed by hot rolling of Q345B steel. Figure 2 As shown, there is one right interlocking plate 1-1, which is fixedly connected to the center of the W-shaped steel sheet pile 1, there are two left interlocking plates 1-2, which are located on both sides, and rod insertion holes 1-3 are respectively provided on the left interlocking plate 1-2 and the right interlocking plate 1-1, there are multiple W-shaped steel sheet piles 1, and the W-shaped steel sheet piles 1 are connected end to end, the left interlocking plates 1-2 of adjacent W-shaped steel sheet piles 1 are opposite to the rod insertion holes 1-3 of the right interlocking plates 1-1, and the rod insertion holes 1-3 are provided with rods 1-4, so as to realize the splicing of the W-shaped steel sheet piles 1;

[0036] Specifically, if Figure 2 As shown, water-stop steel plates 1-5 are fixedly connected between adjacent W-shaped steel sheet piles 1, and the water-stop steel plates 1-5 are vertically arranged;

[0037] Specifically, the bagged clay 2 is composed of an outer snakeskin woven bag 2-1 and an inner toughness waterproof plastic bag 2-2, with clay inside, and the clay 4 is preferably filled to 3 / 4 of the bag volume;

[0038] Specifically, if Figure 4 As shown, a rubber water stop 7 is provided on the water-facing surface of the rubble concrete cofferdam body 6, and the rubber water stop 7 is fixedly connected to the rubble concrete cofferdam body 6 through a fixing bolt 13, and slopes formed by bagged clay 2 are respectively provided on both sides of the rubble concrete cofferdam body 6, and the slopes are respectively at an angle of 45°, and a felt layer 8 is respectively provided inside the slopes;

[0039] Specifically, the felt layer 8 on the side close to the water-facing surface is tilted, and the felt layer 8 on the side away from the water-facing surface is vertically arranged;

[0040] Specifically, a plastic steel grating 9 is provided on the slope surface near the water-facing surface. The plastic steel grating 9 is a mesh steel-plastic composite geogrid made of high-strength steel wire and high-density polyethylene. The plastic steel grating 9 is fixedly connected to the rough stone concrete cofferdam body 6 through a tie rod 10;

[0041] Specifically, the tie rod 10 includes a rod body 10-1, one end of the rod body 10-1 is connected to an anchor head 10-7 through an upper pull ring 10-4 and a lower pull ring 10-5, a pad 10-6 is fixedly connected to the anchor head 10-7, the anchor head 10-7 is fixed inside the rubble concrete cofferdam body 6, the rod body 10-1 passes through the holes of the bagged clay 2 and the plastic steel grating 9 and is fixedly connected with a bolt 10-3 to impose constraints on the bagged clay 2, and a gasket 10-2 is provided between the bolt 10-3 and the plastic steel grating 9.

[0042] Specifically, if Figure 6 As shown, the rubble stone concrete cofferdam body 6 is arranged in sections, that is, cast in sections, and construction joints 14 are arranged between adjacent rubble stone concrete cofferdam bodies 6. A connecting steel plate 15 is arranged on the left and right sides of each section of the rubble stone concrete cofferdam body 6. The connecting steel plate 15 is located in the construction joint 14, and the width of the construction joint 14 is not greater than 30 mm; the connecting steel plate 15 is welded by a U-shaped steel plate 15-1 and a T-shaped steel plate 15-2, and the T-shaped steel plate 15-2 is pre-embedded in the rubble stone concrete cofferdam body 6; the U-shaped steel plate 15- 1 is a U-shaped thin plate with a groove, and its thickness is not more than 15mm. The U-shaped steel plate 15-1 extends out of the outer side of the rubble concrete cofferdam body 6. The opening directions of the U-shaped steel plates 15-1 on the left and right sides of the rubble concrete cofferdam body 6 are opposite. The right U-shaped steel plate 15-1 of the front rubble concrete cofferdam body 6 is plugged with the left U-shaped steel plate 15-1 of the rear rubble concrete cofferdam body 6 to ensure that the rubble concrete cofferdam bodies 6 at both ends are firmly connected; the settlement joint 14 and the U-shaped steel plate 15-1 plug-in are filled with flexible waterproof glue 16.

[0043] like Figure 4 As shown, the rubble stone concrete cofferdam body 6 is constructed by a three-step pouring method. First, the bottom layer of the rubble stone concrete cofferdam body 6 is poured, and a joint stone 11 is pre-buried on the upper surface of the bottom layer; the length of the joint stone 11 is not less than 30 cm, the thickness is not less than 8 cm, and the exposed concrete surface is not less than 15 cm, to ensure that the strength of the cofferdam connection meets the design requirements; the joint stones 11 are 0.5 m in horizontal spacing and 0.5 m in vertical spacing, and are arranged in a plum blossom shape; then the middle part of the rubble stone concrete cofferdam body 6 is poured, and two straight A tie bar 12 with a diameter of 40 mm is provided; one end of the tie bar 12 penetrates into the bottom layer of the rubble stone concrete cofferdam body 6, and the other end is located in the middle of the rubble stone concrete cofferdam body 6; a joint stone 11 is pre-embedded on the upper surface of the middle of the rubble stone concrete cofferdam body 6, and the requirements of the joint stone 11 are the same as those of the bottom layer; finally, the upper part of the rubble stone concrete cofferdam body 6 is poured, and two tie bars 12 with a diameter of 40 mm are arranged on both sides; one end of the tie bar 12 penetrates into the middle of the rubble stone concrete cofferdam body 6, and the other end is located in the upper part of the rubble stone concrete cofferdam body 6.

[0044] When the utility model is used, W-shaped steel sheet piles 1 are first assembled, and after the W-shaped steel sheet piles 1 are connected end to end, the insertion rods 1-4 are inserted into the insertion rod holes 1-3, and a temporary earth bag cofferdam is built through strip clay 2, waterproof geotextile 3 and clay 4. After the water inside the temporary earth bag cofferdam is evacuated, a concrete cushion layer 5 is poured, and a rubble concrete cofferdam body 6 is poured on the concrete cushion layer 5. Bags of clay 2 are arranged on both sides of the rubble concrete cofferdam body 6, and the bagged clay 2 is constrained by tie rods 10 and plastic steel grilles 9, and then the temporary earth bag cofferdam is removed to complete the construction.

[0045] A composite cofferdam construction method suitable for river channel construction comprises the following steps:

[0046] S1. Control the construction water level, conduct surveying and setting out, determine the location of the temporary earthbag cofferdam and rough stone concrete cofferdam, and prepare for construction;

[0047] S2. Combine W-shaped steel sheet piles according to the shape of the cofferdam, and insert the W-shaped steel sheet piles into the riverbed with a depth of not less than 1m; construct a temporary earthbag cofferdam, and fill bagged clay in layers on both sides of the W-shaped steel sheet piles. The height of each layer is designed to be 0.5m, and the bagged clay is determined according to the specific conditions on site; lay a layer of waterproof geotextile on the bagged clay slope and the top of the slope, and lay a certain thickness of clay on the water-facing surface of the bagged clay slope;

[0048] S3. Pump out the water inside the temporary earthbag cofferdam, and apply C30 concrete cushion layer at the layout position of the rubble concrete cofferdam; after the cushion layer is constructed and reaches the designed strength, pour the rubble concrete in three layers; when pouring, first lay a layer of 8-15cm thick concrete as a base, and then lay the rubble. The rubble should be laid evenly, with the large surface facing downward and the small surface facing upward, and the texture of the stone should be perpendicular to the force direction; the spacing between the rubble should be no less than 5cm, and the distance from the formwork should be no less than 15cm to ensure that each stone is wrapped in concrete; after the rubble is half inserted into the concrete, pour in concrete to fill all the gaps; then lay the rubble concrete layer by layer until the top surface, keeping the top surface of the rubble covered with no less than 10cm of concrete, and the number of rubble should be controlled not to exceed 25% of the foundation volume; a settlement joint is set every 15m on the main body of the rubble concrete cofferdam to maintain the main body of the rubble concrete cofferdam.

[0049] S4. An external rubber waterstop is used on the water-facing side of the main structure of the rubble concrete cofferdam, which is fixed by fixing bolts; bagged clay is then filled in layers on the water-facing and water-receiving sides of the main structure of the rubble concrete cofferdam, and a layer of tarpaulin is laid at the designed position; a steel-plastic grating is laid on the outside of the bagged clay on the water-facing side of the main structure of the rubble concrete cofferdam, and the bagged clay is firmly connected to the main structure of the rubble concrete cofferdam through the combined action of tie rods and the steel-plastic grating.

[0050] S5. Remove the temporary earthbag cofferdam and carry out subsequent construction work.

[0051] Specifically, the main body of the rubble stone concrete cofferdam is constructed by a three-step casting method. First, the bottom layer of the main body of the rubble stone concrete cofferdam is cast, and joint stones are embedded on the upper surface of the bottom layer. The length of the joint stones is not less than 30 cm, the thickness is not less than 8 cm, and the exposed concrete surface is not less than 15 cm. The joint stones have a horizontal spacing of 0.5 m and a vertical spacing of 0.5 m, and are arranged in a plum blossom shape. Then, the middle part of the main body of the rubble stone concrete cofferdam is cast, and two tie bars with a diameter of 40 mm are set on each side. One end of the tie bar penetrates into the bottom layer of the main body of the rubble stone concrete cofferdam, and the other end is located in the middle of the main body of the rubble stone concrete cofferdam. Joint stones are embedded on the upper surface of the middle part of the main body of the rubble stone concrete cofferdam, and the requirements for the joint stones are the same as those for the bottom layer. Finally, the upper part of the main body of the rubble stone concrete cofferdam is cast, and two tie bars with a diameter of 40 mm are set on each side. One end of the tie bar penetrates into the middle of the main body of the rubble stone concrete cofferdam, and the other end is located on the upper part of the main body of the rubble stone concrete cofferdam.

[0052] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0053] Finally, it should be noted that the above description is only a preferred embodiment of the utility model and is not intended to limit the utility model. Although the utility model is described in detail with reference to the above embodiments, those skilled in the art can still modify the technical solutions recorded in the above embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A composite cofferdam suitable for river channel construction, comprising a temporary earthbag cofferdam and a rough stone concrete cofferdam, characterized in that: The earthbag temporary cofferdam comprises a W-shaped steel sheet pile (1), bagged clay (2) arranged on both sides of the W-shaped steel sheet pile (1), and a waterproof geotextile (3) laid on the surface of the bagged clay (2), wherein clay (4) is laid on the surface of the waterproof geotextile (3) on the side corresponding to the water-facing side; The rubble concrete cofferdam is arranged on a side of the earthbag temporary cofferdam away from the water surface, and the rubble concrete cofferdam comprises a rubble concrete cofferdam body (6), a concrete cushion layer (5) is arranged at the bottom of the rubble concrete cofferdam body (6), and a protrusion for connecting with the concrete cushion layer (5) is arranged at the bottom of the rubble concrete cofferdam body (6).

2. A composite cofferdam suitable for river channel construction according to claim 1, characterized in that: The W-shaped steel sheet pile (1) is provided with a left interlocking plate (1-2) and a right interlocking plate (1-1) on both sides, and rod insertion holes (1-3) are provided on the left interlocking plate (1-2) and the right interlocking plate (1-1). There are a plurality of W-shaped steel sheet piles (1), and the W-shaped steel sheet piles (1) are connected end to end. The rod insertion holes (1-3) of the left interlocking plates (1-2) and right interlocking plates (1-1) of adjacent W-shaped steel sheet piles (1) are opposite to each other, and rod insertion holes (1-4) are provided in the rod insertion holes (1-3).

3. A composite cofferdam suitable for river channel construction according to claim 2, characterized in that: Waterstop steel plates (1-5) are fixedly connected between adjacent W-shaped steel sheet piles (1).

4. A composite cofferdam suitable for river channel construction according to claim 3, characterized in that: The bagged clay (2) is composed of an outer snakeskin woven bag (2-1) and an inner toughness waterproof plastic bag (2-2), and clay is contained inside.

5. A composite cofferdam suitable for river channel construction according to any one of claims 1 to 4, characterized in that: A rubber water stop (7) is provided on the water-facing surface of the rubble concrete cofferdam body (6), and the rubber water stop (7) is fixedly connected to the rubble concrete cofferdam body (6) via a fixing bolt (13). Slopes formed by bagged clay (2) are provided on both sides of the rubble concrete cofferdam body (6), and a felt layer (8) is provided inside the slopes.

6. A composite cofferdam suitable for river channel construction according to claim 5, characterized in that: The felt layer (8) on the side close to the water-facing surface is arranged obliquely, and the felt layer (8) on the side away from the water-facing surface is arranged vertically.

7. A composite cofferdam suitable for river channel construction according to claim 6, characterized in that: A plastic steel grille (9) is provided on the slope surface on one side close to the water-facing surface, and the plastic steel grille (9) is fixedly connected to the rough stone concrete cofferdam body (6) via a tie rod (10).

8. A composite cofferdam suitable for river channel construction according to claim 7, characterized in that: The tie rod (10) comprises a rod body (10-1), one end of the rod body (10-1) is connected to an anchor head (10-7) via an upper pull ring (10-4) and a lower pull ring (10-5), a pad (10-6) is fixedly connected to the anchor head (10-7), the anchor head (10-7) is fixed inside a rough stone concrete cofferdam body (6), the rod body (10-1) passes through holes in bagged clay (2) and a plastic steel grille (9) and is fixedly connected to a bolt (10-3), and a gasket (10-2) is provided between the bolt (10-3) and the plastic steel grille (9).

9. A composite cofferdam suitable for river channel construction according to any one of claims 1 to 4, characterized in that: The rubble stone concrete cofferdam bodies (6) are arranged in sections, and construction joints (14) are arranged between adjacent rubble stone concrete cofferdam bodies (6). Adjacent rubble stone concrete cofferdam bodies (6) are connected via connecting steel plates (15).

10. A composite cofferdam suitable for river channel construction according to claim 9, characterized in that: The connecting steel plate (15) comprises a T-shaped steel plate (15-2) fixed inside the rubble concrete cofferdam body (6); a U-shaped steel plate (15-1) is provided on one side of the T-shaped steel plate (15-2) away from the corresponding rubble concrete cofferdam body (6); and the U-shaped steel plates (15-1) of adjacent connecting steel plates (15) are interlocked.

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