Composite cofferdam structure for deepwater channel expanding excavation construction and construction method of composite cofferdam structure

Abstract

The invention provides a deepwater channel expanding excavation construction composite cofferdam structure and a construction method thereof. The deepwater channel expanding excavation construction composite cofferdam structure comprises a composite cofferdam structure body arranged on a channel and located on the periphery of a to-be-excavated area. The composite cofferdam structure comprises inner side lock catch steel pipe piles located on the inner side, outer side lock catch steel pipe piles are arranged on the outer sides of the inner side lock catch steel pipe piles, and a first inclined inner side lock catch steel pipe pile and a second inclined inner side lock catch steel pipe pile are arranged between the two ends of each inner side lock catch steel pipe pile and an embankment correspondingly. A first oblique outer side lock catch steel pipe pile and a second oblique outer side lock catch steel pipe pile are arranged between the two ends of the outer side lock catch steel pipe pile and the embankment correspondingly. The cofferdam structure can be suitable for deepwater channel expanding excavation construction under the complex stratum condition, has good structural stability and water sealing performance, and not only can guarantee construction safety during deepwater channel expanding excavation construction, but also can guarantee traffic safety of an existing channel; in addition, the construction efficiency of channel expanding excavation construction is effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of channel excavation construction, and in particular to a composite cofferdam structure for deep-water channel expansion construction and a construction method thereof. Background Art

[0002] At present, it is necessary to construct a construction cofferdam during the construction of waterway excavation to provide a corresponding construction environment for subsequent procedures. Especially in the construction of waterway expansion, it is necessary to consider not only the complex water environment but also the requirements of navigation, which makes the implementation of the cofferdam more difficult. At present, the commonly used cofferdam structures in the construction of waterway expansion are steel sheet pile cofferdam and steel pipe pile cofferdam. However, steel sheet pile cofferdam is generally suitable for shallow water depth and cannot be used as a cofferdam for deepwater waterway expansion construction. Steel pipe pile cofferdam can be used as a deepwater construction cofferdam, but due to the certain gap between the steel pipes, the cofferdam is easily deformed under the action of water pressure, which makes it more difficult to seal the water. During the implementation process, the water sealing layer needs to be repaired many times, which leads to an increase in construction cost. Summary of the invention

[0003] In view of the problems existing in the above-mentioned conventional methods, the present invention aims to provide a composite cofferdam structure for deep-water channel excavation construction and a construction method thereof. This cofferdam structure can be suitable for deep-water channel excavation construction under complex geological conditions, and has good structural stability and water sealing performance. It can not only ensure the construction safety during the deep-water channel excavation construction, but also ensure the safety of passage of existing waterways. In addition, it effectively improves the construction efficiency of channel excavation construction.

[0004] In order to achieve the above technical features, the object of the present invention is achieved as follows: A composite cofferdam structure for deepwater channel expansion construction includes a composite cofferdam structure arranged on the channel and located outside the proposed excavation area; The composite cofferdam structure includes an inner locking steel pipe pile located on the inner side, an outer locking steel pipe pile is arranged on the outer side of the inner locking steel pipe pile, a first oblique inner locking steel pipe pile and a second oblique inner locking steel pipe pile are respectively arranged between the two ends of the inner locking steel pipe pile and the embankment, and a first oblique outer locking steel pipe pile and a second oblique outer locking steel pipe pile are respectively arranged between the two ends of the outer locking steel pipe pile and the embankment.

[0005] The inner locking steel pipe pile, the outer locking steel pipe pile, the first oblique inner locking steel pipe pile, the first oblique outer locking steel pipe pile, the second oblique inner locking steel pipe pile and the second oblique outer locking steel pipe pile all adopt the same structural form, and respectively include a main steel pipe, a locking pipe with a notch is welded and fixed on the outer wall of the main steel pipe, and a locking plate is symmetrically welded and fixed on the other side of the outer wall of the main steel pipe; adjacent main steel pipes are locked together by the locking pipe and the locking plate.

[0006] The locking tube is made by cutting a steel tube, and the locking plate is made by cutting an I-beam; During installation, one end of the locking plate is inserted into the locking tube from the notch; The internal space of the locking tube is filled with a locking tube filler, and the locking tube filler is clay, sawdust or a compressible plastic strip.

[0007] The outer reinforcing ribs and the inner reinforcing ribs are symmetrically welded and fixed on the upper outer walls of the inner locking steel pipe pile, the outer locking steel pipe pile, the first oblique inner locking steel pipe pile, the first oblique outer locking steel pipe pile, the second oblique inner locking steel pipe pile and the second oblique outer locking steel pipe pile, and the inner reinforcing ribs are processed with pin holes at certain intervals, and cross-arranged scissor struts are hinged between the inner reinforcing ribs between the inner locking steel pipe pile and the outer locking steel pipe pile, and the two ends of the scissor struts are hingedly connected to the corresponding pin holes through pins, and the end of the pin is provided with a safety card.

[0008] The bottom end of the main steel pipe is buried in the pile hole, and the pile hole passes through the covering layer, the permeable layer and the impermeable layer of the waterway in sequence, and the pile hole penetrates into the impermeable layer by at least 5m; The gap between the main steel pipe and the pile hole is sealed by clay.

[0009] The cavity between the inner locking steel pipe pile and the outer locking steel pipe pile is filled with an inter-pile filler; The inter-pile filling material is clay.

[0010] The outer reinforcing ribs are provided with wire pulling holes at regular intervals, and the wire pulling holes are connected with anchoring devices; The anchor pulling device comprises a pull wire, one end of which is connected to the pull wire hole, and the other end is connected to the anchor arranged on the natural foundation, and an adjustment device for adjusting the tension degree is arranged in the middle of the pull wire; A tension sensor is provided inside the regulating device, and the tension sensor senses the impact of water level changes on the pull line to avoid the pull line breaking due to excessive stress or the cofferdam becoming unstable due to insufficient stress. The tension of the pull line is adjusted through the regulating device to avoid the tension exceeding the standard or being too small, so that the tension is controlled within an appropriate threshold.

[0011] Top pressure walkway plates are arranged on the tops of the inner locking steel pipe pile, the outer locking steel pipe pile, the first oblique inner locking steel pipe pile, the first oblique outer locking steel pipe pile, the second oblique inner locking steel pipe pile and the second oblique outer locking steel pipe pile.

[0012] The main steel pipe is provided with steel pipe filling material inside, and the steel pipe filling material is sand, pebbles or gravel.

[0013] A construction method for a composite cofferdam structure for deepwater channel expansion and excavation, comprising the following steps: Step 1, excavation of pile hole: Set up the guide frame, use the rotary drilling rig to drill holes for the foundation of the waterway, and ensure that the final pile hole depth must reach a certain depth inside the impermeable layer; Step 2, backfilling of pile hole: The clay is transported to the vicinity of the pile hole by ship, and then the pile hole is backfilled with clay; Step 3: Piling and fixing of locking steel pipe piles: Prefabricate the locking steel pipe piles in advance at the side of the arrangement, use a lifting device to suspend the vibrating hammer to drive the locking steel pipe piles, and adopt the vibration pile-making process; Step 4, installation of scissor brace: An outer reinforcing rib is fixed on the outer side of the locking steel pipe pile, an inner reinforcing rib is fixed on the inner side of the locking steel pipe pile, and then a scissor brace is hinged between the inner reinforcing ribs through a pin shaft, thereby connecting all the locking steel pipe piles into a whole; Step 5, installation of anchoring device: Connecting an anchor device to the outer reinforcement rib of the locking steel pipe pile; Step 6, filling of locking steel pipe piles: After all the locking steel pipe piles are fixed, the inside of the main steel pipe is backfilled with steel pipe filler, and the inside of the locking pipe is backfilled with locking pipe filler; Step 7, filling between locking steel pipe piles: The space between the inner locking steel pipe pile and the outer locking steel pipe pile is filled with an inter-pile filler; Step 8, installation of the top walkway board: A top-pressing walkway plate is fixedly installed on the top of the locking steel pipe pile; Step 9, Pumping of foundation pit: After the entire composite cofferdam structure and the embankment are sealed, water is pumped out from the foundation pit in the enclosed area until a water-free construction area is formed, creating a water-free environment for the planned excavation area.

[0014] The present invention has the following beneficial effects: 1. The cofferdam structure of the present invention can be applied to deep-water channel excavation construction under complex geological conditions, and has good structural stability and water sealing performance. It can not only ensure the construction safety during the deep-water channel excavation construction, but also ensure the traffic safety of the existing waterway; in addition, it effectively improves the construction efficiency of the channel excavation construction.

[0015] 2. By adopting the above-mentioned locking steel pipe piles, a reliable locking connection between adjacent main steel pipes can be achieved, thereby ensuring the reliability of the connection between adjacent main steel pipes, and at the same time ensuring the sealing performance of the corresponding inner locking steel pipe piles and outer locking steel pipe piles, while simplifying the installation process and improving installation efficiency.

[0016] 3. Through the arrangement of the above-mentioned scissor braces, the connection strength and stability between the inner locking steel pipe piles and the outer locking steel pipe piles are enhanced.

[0017] 4. The filling material between the piles ensures that the cofferdam has good water-sealing performance and resists the buoyancy generated by pumping water in the foundation pit.

[0018] 5. The stability and reliability of the composite cofferdam structure are effectively enhanced by adopting the anchor device.

[0019] 6. The above-mentioned adjustment device enhances the anchoring reliability of the entire composite cofferdam structure.

[0020] 7. The above-mentioned top-pressing walkway slab can also adopt a prefabricated slab with a limiting device. The top-pressing device connects the locking steel pipe piles as a whole through the limiting device to increase the overall rigidity. At the same time, the walkway slab can form a passage as a passage during the construction process.

[0021] 8. Use steel pipe filling material to increase the overall cofferdam's ability to resist overturning force. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0023] Figure 1 It is a schematic plan view of the composite cofferdam structure for deep-water channel expansion construction according to the present invention.

[0024] Figure 2 It is a schematic elevation diagram of the composite cofferdam structure for deep-water channel expansion construction according to the present invention.

[0025] Figure 3 It is a schematic diagram of the scissors support and reinforcing rib connection device of the present invention.

[0026] Figure 4 It is a schematic diagram of the structure of the locking steel pipe pile unit of the present invention.

[0027] Figure 5 This is a diagram of the pile hole excavation process in the construction method of the composite cofferdam structure for deep-water channel expansion construction of the present invention.

[0028] Figure 6 This is a diagram of the pile hole backfilling process in the construction method of the composite cofferdam structure for deep-water channel expansion construction of the present invention.

[0029] Figure 7It is a diagram of the piling and fixing process of the locking steel pipe piles in the construction method of the composite cofferdam structure for deep-water channel expansion construction of the present invention.

[0030] Figure 8 This is a diagram of the installation process of the scissors support in the construction method of the composite cofferdam structure for deep-water channel expansion construction of the present invention.

[0031] Fig. 9 This is a diagram of the filling between the locking steel pipe piles and the installation process of the top-pressing walkway plate in the construction method of the composite cofferdam structure for deep-water channel expansion construction of the present invention.

[0032] In the figure: first oblique inner locking steel pipe pile 1, first oblique outer locking steel pipe pile 2, embankment 3, inner locking steel pipe pile 4, outer locking steel pipe pile 5, planned excavation area 6, second oblique inner locking steel pipe pile 7, second oblique outer locking steel pipe pile 8, channel 9, structure 10, top pressure walkway plate 11, outer reinforcing rib 12, wire hole 32, adjustment device 14, anchor 15, inner reinforcing rib 16, scissor support 17, pile filling 18, pile hole 19, clay 20, cover layer 21, permeable layer 22, impermeable layer 23, steel pipe filling material 24, pin hole 25, locking plate 26, main steel pipe 27, locking pipe 28, locking pipe filling 29, composite cofferdam structure 30, gap 31, wire hole 32 DETAILED DESCRIPTION The embodiments of the present invention are further described below in conjunction with the accompanying drawings.

[0033] Embodiment 1: See also Figure 1-9 A composite cofferdam structure for deepwater channel excavation construction includes a composite cofferdam structure 30 arranged on a channel 9 and located outside a planned excavation area 6; the composite cofferdam structure 30 includes an inner locking steel pipe pile 4 located inside, an outer locking steel pipe pile 5 is arranged outside the inner locking steel pipe pile 4, a first oblique inner locking steel pipe pile 1 and a second oblique inner locking steel pipe pile 7 are arranged between the two ends of the inner locking steel pipe pile 4 and the embankment 3, and a first oblique outer locking steel pipe pile 2 and a second oblique outer locking steel pipe pile 8 are arranged between the two ends of the outer locking steel pipe pile 5 and the embankment 3. This cofferdam structure can be applied to deepwater channel excavation construction under complex geological conditions, has good structural stability and water sealing performance, can not only ensure the construction safety during the deepwater channel excavation construction, but also ensure the traffic safety of the existing channel; in addition, it effectively improves the construction efficiency of channel excavation construction.

[0034] Furthermore, the inner locking steel pipe pile 4, the outer locking steel pipe pile 5, the first oblique inner locking steel pipe pile 1, the first oblique outer locking steel pipe pile 2, the second oblique inner locking steel pipe pile 7 and the second oblique outer locking steel pipe pile 8 all adopt the same structural form, and respectively include a main steel pipe 27, a locking pipe 28 with a notch 31 is welded and fixed on the outer wall of the main steel pipe 27, and a locking plate 26 is symmetrically welded and fixed on the other side of the outer wall of the main steel pipe 27; adjacent main steel pipes 27 are locked together by the locking pipe 28 and the locking plate 26. By adopting the above-mentioned locking steel pipe piles, a reliable locking connection between adjacent main steel pipes 27 can be achieved, thereby ensuring the reliability of the connection between adjacent main steel pipes 27, and at the same time ensuring the sealing performance of the corresponding inner locking steel pipe pile 4 and the outer locking steel pipe pile 5, while simplifying the installation process and improving the installation efficiency.

[0035] Furthermore, the locking tube 28 is made by cutting a steel tube, and the locking plate 26 is made by cutting an I-beam. By making the above materials, the production cost of the corresponding locking steel pipe pile is effectively reduced, and the production process is simplified.

[0036] Furthermore, during installation, one end of the locking plate 26 is inserted into the interior of the locking tube 28 from the notch 31 ; through the above-mentioned locking connection method, a reliable connection between adjacent main steel pipes 27 can be achieved.

[0037] Among them, the locking steel pipe piles are constructed by using a rotary drill to guide the holes, a vibratory hammer to form the piles, and clay to seal them. The locking steel pipe piles must be buried below the impermeable layer.

[0038] Furthermore, the internal space of the locking tube 28 is filled with a locking tube filler 29 , and the locking tube filler 29 is made of clay, sawdust or compressible plastic strips.

[0039] Furthermore, outer reinforcing ribs 12 and inner reinforcing ribs 16 are symmetrically welded and fixed on the upper outer walls of the inner locking steel pipe pile 4, the outer locking steel pipe pile 5, the first oblique inner locking steel pipe pile 1, the first oblique outer locking steel pipe pile 2, the second oblique inner locking steel pipe pile 7 and the second oblique outer locking steel pipe pile 8, the inner reinforcing ribs 16 are processed with pin holes 25 at certain intervals, and cross-arranged scissor struts 17 are hinged between the inner reinforcing ribs 16 between the inner locking steel pipe pile 4 and the outer locking steel pipe pile 5, and the two ends of the scissor struts 17 are hingedly connected to the corresponding pin holes 25 through pins, and the ends of the pins are provided with safety cards. The arrangement of the above-mentioned scissor struts 17 enhances the connection strength and stability between the inner locking steel pipe pile 4 and the outer locking steel pipe pile 5.

[0040] Furthermore, the bottom end of the main steel pipe 27 is buried inside the pile hole 19, and the pile hole 19 sequentially passes through the cover layer 21, the permeable layer 22 and the impermeable layer 23 of the waterway 9, and the pile hole 19 penetrates at least 5 meters into the impermeable layer 23. By adopting the above-mentioned depth arrangement, water seepage at the bottom is prevented.

[0041] Furthermore, the gap between the main steel pipe 27 and the pile hole 19 is sealed by clay 20. The clay 20 ensures that the cofferdam has good water sealing performance and resists the buoyancy generated by pumping water in the foundation pit.

[0042] Furthermore, the cavity between the inner locking steel pipe pile 4 and the outer locking steel pipe pile 5 is filled with an inter-pile filler 18. The inter-pile filler 18 ensures that the cofferdam has a good water sealing performance and resists the buoyancy generated by pumping water in the foundation pit.

[0043] Furthermore, the inter-pile filler 18 is made of clay, and the sealing effect is ensured by using clay.

[0044] Furthermore, the outer reinforcing rib 12 is provided with wire holes 32 at certain intervals, and the wire holes 32 are connected with anchoring devices; the anchoring devices include wires 13, one end of which is connected to the wire holes 32, and the other end is connected to an anchor 15 provided on a natural foundation, and an adjusting device 14 for adjusting the tensioning degree is provided in the middle of the wires 13. The use of the anchoring device effectively enhances the stability and reliability of the composite cofferdam structure 30.

[0045] Furthermore, a tension sensor is provided inside the adjusting device 14, and the tension sensor senses the influence of water level changes on the tension wire 13, so as to avoid the tension wire 13 from breaking due to excessive stress or the cofferdam from becoming unstable due to insufficient stress. The tension of the tension wire 13 is adjusted by the adjusting device 14 to avoid the tension from exceeding the standard or being too small, so that the tension is controlled within a suitable threshold. The above-mentioned adjusting device 14 enhances the anchoring reliability of the entire composite cofferdam structure 30.

[0046] Furthermore, a top-pressing walkway plate 11 is provided on the top of the inner locking steel pipe pile 4, the outer locking steel pipe pile 5, the first oblique inner locking steel pipe pile 1, the first oblique outer locking steel pipe pile 2, the second oblique inner locking steel pipe pile 7 and the second oblique outer locking steel pipe pile 8. The top-pressing walkway plate 11 can also be a prefabricated plate with a limiting device. The top-pressing device connects the locking steel pipe piles as a whole through the limiting device to increase the overall rigidity. At the same time, the walkway plate can form a passage as a passage during the construction process.

[0047] Furthermore, a steel pipe filler 24 is arranged inside the main steel pipe 27, and the steel pipe filler 24 is made of sand, pebbles or gravel. The steel pipe filler 24 increases the overall resistance of the cofferdam to overturning force.

[0048] Embodiment 2: A construction method for a composite cofferdam structure for deepwater channel expansion and excavation, comprising the following steps: Step 1, excavation of pile hole 19: Set up a guide frame, use a rotary drilling rig to drill holes on the foundation of the waterway 9, and ensure that the depth of the pile hole 19 finally formed must enter a certain depth inside the impermeable layer 23; Step 2, backfilling of pile hole 19: The clay 20 is transported to the vicinity of the hole opening of the pile hole 19 by ship, and then the clay 20 is backfilled into the pile hole 19; Step 3: Piling and fixing of locking steel pipe piles: Prefabricate the locking steel pipe piles in advance at the side of the arrangement, use a lifting device to suspend the vibrating hammer to drive the locking steel pipe piles, and adopt the vibration pile-making process; Step 4, installation of the scissors support 17: An outer reinforcing rib 12 is fixed on the outer side of the locking steel pipe pile, and an inner reinforcing rib 16 is fixed on the inner side of the locking steel pipe pile. Then, a scissor brace 17 is hinged between the inner reinforcing ribs 16 through a pin shaft, thereby connecting all the locking steel pipe piles into a whole. Step 5, installation of anchoring device: Connect an anchor device to the outer reinforcing rib 12 of the locking steel pipe pile; Step 6, filling of locking steel pipe piles: After all the locking steel pipe piles are fixed, the interior of the main steel pipe 27 is backfilled with steel pipe filler 24, and the interior of the locking pipe 28 is backfilled with locking pipe filler 29; Step 7, filling between locking steel pipe piles: The space between the inner locking steel pipe pile 4 and the outer locking steel pipe pile 5 is filled with an inter-pile filler 18; Step 8, installation of the top aisle plate 11: A top-pressing walkway plate 11 is fixedly installed on the top of the locking steel pipe pile; Step 9, Pumping of foundation pit: After the entire composite cofferdam structure 30 and the embankment 3 are sealed, water is pumped out from the foundation pit in the closed area until a water-free construction area is formed, thereby creating a water-free environment for the planned excavation area 6 .

Claims

1. A composite cofferdam structure for deep-water channel expansion construction, characterized in that: It includes a composite cofferdam structure (30) arranged on the waterway (9) and located outside the proposed excavation area (6); The composite cofferdam structure (30) comprises an inner locking steel pipe pile (4) located inside, an outer locking steel pipe pile (5) is arranged outside the inner locking steel pipe pile (4), a first oblique inner locking steel pipe pile (1) and a second oblique inner locking steel pipe pile (7) are arranged between the two ends of the inner locking steel pipe pile (4) and the embankment (3), and a first oblique outer locking steel pipe pile (2) and a second oblique outer locking steel pipe pile (8) are arranged between the two ends of the outer locking steel pipe pile (5) and the embankment (3).

2. A composite cofferdam structure for deepwater channel expansion construction according to claim 1, characterized in that: The inner locking steel pipe pile (4), the outer locking steel pipe pile (5), the first oblique inner locking steel pipe pile (1), the first oblique outer locking steel pipe pile (2), the second oblique inner locking steel pipe pile (7) and the second oblique outer locking steel pipe pile (8) all adopt the same structural form and respectively comprise a main steel pipe (27), a locking pipe (28) with a notch (31) being welded and fixed on the outer wall of the main steel pipe (27), and a locking plate (26) being symmetrically welded and fixed on the other side of the outer wall of the main steel pipe (27); adjacent main steel pipes (27) are locked and matched between the locking pipes (28) and the locking plates (26).

3. A composite cofferdam structure for deepwater channel expansion construction according to claim 2, characterized in that: The locking tube (28) is made by cutting a steel tube, and the locking plate (26) is made by cutting an I-beam; During installation, one end of the locking plate (26) is inserted into the interior of the locking tube (28) through the notch (31); The internal space of the locking tube (28) is filled with a locking tube filler (29), and the locking tube filler (29) is made of clay, sawdust or a compressible plastic strip.

4. A composite cofferdam structure for deepwater channel expansion construction according to claim 2, characterized in that: The outer reinforcing ribs (12) and the inner reinforcing ribs (16) are symmetrically welded and fixed on the upper outer walls of the inner locking steel pipe pile (4), the outer locking steel pipe pile (5), the first oblique inner locking steel pipe pile (1), the first oblique outer locking steel pipe pile (2), the second oblique inner locking steel pipe pile (7) and the second oblique outer locking steel pipe pile (8), the inner reinforcing ribs (16) are processed with pin holes (25) at a certain interval, and cross-arranged scissor struts (17) are hinged between the inner reinforcing ribs (16) between the inner locking steel pipe pile (4) and the outer locking steel pipe pile (5), and the two ends of the scissor struts (17) are hingedly connected to the corresponding pin holes (25) through pins, and the ends of the pins are provided with safety cards.

5. The composite cofferdam structure for deepwater channel expansion construction according to claim 2, characterized in that: The bottom end of the main steel pipe (27) is buried inside the pile hole (19), and the pile hole (19) passes through the covering layer (21), the permeable layer (22) and the impermeable layer (23) of the waterway (9) in sequence, and the pile hole (19) penetrates into the impermeable layer (23) by at least 5m; The gap between the main steel pipe (27) and the pile hole (19) is sealed by clay (20).

6. A composite cofferdam structure for deepwater channel expansion construction according to claim 2, characterized in that: The cavity between the inner locking steel pipe pile (4) and the outer locking steel pipe pile (5) is filled with an inter-pile filler (18); The inter-pile filler (18) is made of clay.

7. A composite cofferdam structure for deepwater channel expansion construction according to claim 4, characterized in that: The outer reinforcing rib (12) is provided with wire pulling holes (32) at regular intervals, and the wire pulling holes (32) are connected to anchor pulling devices; The anchor pulling device comprises a pull wire (13), one end of the pull wire (13) is connected to the pull wire hole (32), and the other end is connected to an anchor (15) arranged on a natural foundation, and an adjustment device (14) for adjusting the tensioning degree is arranged in the middle of the pull wire (13); Furthermore, a tension sensor is provided inside the regulating device (14), and the influence of water level changes on the pull wire (13) is sensed by the tension sensor, so as to avoid the pull wire (13) being broken due to excessive stress or the cofferdam being unstable due to insufficient stress. The tension of the pull wire (13) is adjusted by the regulating device (14), so as to avoid the tension being excessive or too insufficient, and the tension is controlled within a suitable threshold.

8. The composite cofferdam structure for deepwater channel expansion construction according to claim 2, characterized in that: A top-pressing walkway plate (11) is provided on the top of the inner locking steel pipe pile (4), the outer locking steel pipe pile (5), the first oblique inner locking steel pipe pile (1), the first oblique outer locking steel pipe pile (2), the second oblique inner locking steel pipe pile (7) and the second oblique outer locking steel pipe pile (8).

9. The composite cofferdam structure for deepwater channel expansion construction according to claim 2, characterized in that: A steel pipe filler (24) is arranged inside the main steel pipe (27), and the steel pipe filler (24) is made of sand, pebbles or gravel.

10. The method for constructing a composite cofferdam structure for deepwater channel expansion construction according to any one of claims 2 to 9, characterized in that: The following steps are involved: Step 1, excavation of pile hole (19): Setting up a guide frame, and using a rotary drilling rig to perform rotary drilling on the foundation of the waterway (9), and ensuring that the depth of the pile hole (19) finally formed must enter a certain depth inside the impermeable layer (23); Step 2, backfilling of pile hole (19): transporting clay (20) to the vicinity of the opening of the pile hole (19) by ship, and then backfilling the pile hole (19) with the clay (20); Step 3: Piling and fixing of locking steel pipe piles: Prefabricate the locking steel pipe piles in advance at the side of the arrangement, use a lifting device to suspend the vibrating hammer to drive the locking steel pipe piles, and adopt the vibration pile-making process; Step 4, installation of the scissor brace (17): An outer reinforcing rib (12) is fixed on the outer side of the locking steel pipe pile, an inner reinforcing rib (16) is fixed on the inner side of the locking steel pipe pile, and then a scissor brace (17) is hingedly connected between the inner reinforcing ribs (16) via a pin shaft, thereby connecting all the locking steel pipe piles into a whole; Step 5, installation of anchoring device: Connecting an anchor device to the outer reinforcing rib (12) of the locking steel pipe pile; Step 6, filling of locking steel pipe piles: After all the locking steel pipe piles are fixed, the interior of the main steel pipe (27) is backfilled with steel pipe filler (24), and the interior of the locking pipe (28) is backfilled with locking pipe filler (29); Step 7, filling between locking steel pipe piles: Filling between the inner locking steel pipe pile (4) and the outer locking steel pipe pile (5) with an inter-pile filler (18); Step 8, installation of the top walkway plate (11): A top-pressing walkway plate (11) is fixedly installed on the top of the locking steel pipe pile; Step 9, Pumping of foundation pit: After the entire composite cofferdam structure (30) and the embankment (3) are sealed, water is pumped out from the foundation pit in the enclosed area until a water-free construction area is formed, thereby creating a water-free environment for the planned excavation area (6).

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