An underwater foundation excavation device and method

Abstract

The application discloses an underwater foundation excavation device, which comprises a ship body, a rotating support and an excavation device; the ship body is connected with the excavation device through the rotating support, so that the excavation device can always keep a horizontal state when being lowered or lifted; a winch device is arranged at the bow of the ship body, and a cable of the winch device is connected with the excavation device; a tension sensor is arranged on the winch device and the rotating support; the excavation device comprises a drainage cover, a hydraulic motor, a rotating bucket wheel, a storage bin and a spiral conveying device; the drainage cover comprises an outer shell and a side end cover, one end of the outer shell is sealingly connected with the side end cover to form the drainage cover which is only open at the lower part, and water pressure sensors and air pressure sensors are arranged outside the drainage cover. The application realizes dry excavation construction of underwater soil.

Description

Technical Field

[0001] This invention belongs to the field of underwater foundation treatment and construction technology. More specifically, this invention relates to an underwater foundation excavation device and method. Background Technology

[0002] Underwater foundation excavation is a crucial construction step in achieving waterway dredging, immersed tunnel foundation leveling, and bridge foundation leveling. Different underwater foundations require different excavation methods and equipment. For shallow water sections with soft strata such as mud, sand, and soil, existing general equipment from the waterway dredging department is sufficient. For deeper water sections, more specialized or custom-made equipment with greater dredging depth is required. For sections with rock strata, underwater blasting is necessary for excavation. Currently, various types of dredgers are used for underwater dredging projects, including trailing suction hoppers, cutter suction hoppers, chain buckets, grab buckets, shovel buckets, and jet dredgers. While the above-mentioned underwater foundation excavation methods address the excavation requirements, traditional underwater foundation excavation also presents the following problems: First, current excavation methods are all open excavation, which easily causes bottom sediment pollutants to suspend and spread during the excavation process, leading to water turbidity and water quality deterioration. Second, the excavated soil has a high water content and generally requires impurity removal, chemical conditioning, and concentration and filtration to form soil with lower water content before it can be disposed of. However, treatment plants require large land areas, numerous equipment, and are costly, with complex and energy-intensive processes. Therefore, there is an urgent need to develop efficient and environmentally friendly underwater foundation excavation equipment. Summary of the Invention

[0003] The purpose of this invention is to provide an underwater foundation excavation device and method that enables a locally dry construction environment, prevents the spread of pollutants, directly reduces the moisture content of the soil, and simplifies the post-processing procedures.

[0004] The technical solution adopted by the present invention to solve this technical problem is: an underwater foundation excavation device, comprising: a hull, a rotating support, and an excavation device; The hull and the excavation device are connected by a swivel support to ensure that the excavation device remains horizontal when it is lowered or raised; a winch is provided at the bow of the hull, and the cable of the winch is connected to the excavation device; tension sensors are installed on both the winch and the swivel support. The excavation equipment includes a drainage cover, a hydraulic motor, a rotating bucket wheel, a storage bin, and a screw conveyor. The drainage cover includes an outer shell and a side end cover. One end of the outer shell and the side end cover are sealed together to form a drainage cover with an opening only at the bottom. A water pressure sensor and a gas pressure sensor are installed on the outside of the drainage cover. An air inlet is installed on the outside of the side end cover. A storage compartment is installed on the inside of the side end cover. The top of the storage compartment is open and the bottom of the storage compartment has a drainage hole. A weighing sensor is installed inside the storage compartment. The other end of the outer shell is a boss structure with mounting holes inside. The rotating bucket wheel includes: a rotating shaft, a turntable, and a bucket; the disc-shaped turntable is coaxially arranged with the rotating shaft, there is a certain gap between the storage bin and the turntable, the bucket is installed at the circumferential end of the turntable, the rotating shaft is installed in the mounting hole through bearings, and the rotating shaft is driven to rotate by a hydraulic motor. The mud shoveled by the bucket enters the storage bin under the drive of the turntable, and is then transported to the hull by a screw conveyor.

[0005] As a further aspect of the present invention, the bucket is a bidirectional bucket, with multiple buckets arranged around the turntable. Each bidirectional bucket is formed by splicing two buckets back to back. The top edge of each bucket is serrated, and the bottom of the bucket is semi-open.

[0006] As a further aspect of the present invention, the bucket is fixed to the turntable via a connector and a support; the support is positioned relative to the turntable, and the turntable and the support are connected via a connector; both sides of the bucket are fixed to the turntable and the support respectively, and the connector is positioned between the two buckets.

[0007] As a further aspect of the present invention, the screw conveyor includes an inclined screw conveyor and a vertical screw conveyor. An inclined spiral conveyor is installed through the side end cover. The inclined spiral conveyor extends into the storage compartment through the opening on the side end cover. The spiral part of the inclined spiral conveyor is driven by a rotary motor. A vertical spiral conveyor is installed at the end of the inclined spiral that is close to the rotary motor. The spiral part of the vertical spiral conveyor is driven by a rotary motor.

[0008] As a further aspect of the present invention, a plurality of air inlets are installed between the inclined screw conveyor and the vertical screw conveyor, and on the vertical screw, and a one-way valve is installed on each air inlet.

[0009] As a further aspect of the present invention, it also includes an air intake system, which includes an air compressor, pipes, and valves; The air pipes from the air compressor form a first branch pipe and a second branch pipe. The first branch pipe is equipped with valve one, which is connected to a four-way valve one. The other three ends of the four-way valve one are connected to exhaust valve one, pressure gauge one, and air inlet pipe one, respectively. Air inlet pipe one is connected to air inlet one. The second branch pipe is equipped with valve two, which is connected to a four-way valve two. The other three ends of the four-way valve two are connected to exhaust valve two, pressure gauge two, and air inlet two, respectively. The pipe between air inlet two and four-way valve two is equipped with valve three, which is used to control the opening and closing of air inlet two.

[0010] The present invention also provides a method for underwater foundation excavation using the aforementioned device, comprising the following steps: S1: The excavation device is lowered to the bottom of the water by the rotation support of the hull and the winch device. During the descent, the height h1 of the bottom of the drainage hood from the water surface is detected by the water pressure sensor, and the air pressure P inside the drainage hood is detected by the air pressure sensor. The air intake of the first air inlet is controlled until the air pressure P reaches the requirement: P=ρgh1, and then the first valve is closed. S2: During descent, the load weight is detected by the tension sensors installed on the winch and support devices. When the load decreases significantly during underwater descent, the excavation device reaches the mud surface. S3: The rotating bucket wheel rotates and begins to dig soil, excavating the soil below the entire drainage hood and pouring the excavated soil into the storage bin. When the soil in the storage bin reaches a certain amount, the screw conveyor is activated to transport the soil to the ship. During the soil conveying process, valves two and three are opened, and high-pressure air is introduced along the conveying path to squeeze out the water in the soil. After reflux, the water is discharged through the drainage hole at the bottom of the storage bin. When it is necessary to reduce the air pressure, valve two is closed, and valve three and exhaust valve two are opened to discharge the air in the screw conveyor. S4: During the dredging process, the ship rotates around the positioning pile to achieve sweeping dredging at the current position. After one layer of soil is excavated, the dredging device is gradually lowered through the rotating support and winch device, and then sweeping dredging is carried out along the previous sweeping path. In this way, the sweeping dredging is repeated and the excavation is continuously deepened. During this process, the rotating bucket wheel reverses. S5: When the vessel is being moved, the excavation device needs to float. Set the floatation height H. At this time, the drainage cover is depressurized by releasing air and adjusting the air pressure inside the drainage cover. S6: After the vessel is moved, the excavation device will submerge again, and the construction will be repeated in this cycle.

[0011] The present invention has at least the following beneficial effects: The underwater foundation excavation device and method realizes dry excavation of underwater soil. It adopts a combination of a mother ship and an underwater excavation device to provide power to the underwater excavation device and maintain its posture. The underwater excavation device uses a polygonal drainage hood. After the excavation device reaches the bottom, high-pressure air is supplied into the drainage hood to drain the water inside, creating a local "dry" construction work area underwater. A rotating bucket wheel and screw conveyor are then used to transport the soil, addressing the problems of complex post-processing, high energy consumption, and significant pollution associated with existing excavation or dredging equipment. High-pressure air is introduced during the screw conveyor's transport process to further squeeze out water from the soil, reducing its moisture content. The rotating bucket wheel, employing both forward and reverse buckets, in conjunction with the vessel's positioning stakes, enables sweeping excavation in underwater conditions, improving construction efficiency.

[0012] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0013] Figure 1 Diagram of underwater foundation excavation equipment; Figure 2 This is a side view of the excavation device according to an embodiment of the present invention; Figure 3 This is a three-dimensional schematic diagram of an excavation device according to an embodiment of the present invention; Figure 4 This is a schematic diagram showing the composition of a hydraulic motor, a rotating shaft, and a housing according to an embodiment of the present invention; Figure 5 This is a front view of the excavation device according to an embodiment of the present invention; Figure 6 This is a schematic diagram showing the arrangement of the second air inlet on the screw conveyor according to an embodiment of the present invention; Figure 7 This is a diagram showing the air intake system of an excavation device according to an embodiment of the present invention; Figure 8 This is a sweeping excavation diagram of a single station of the excavation device according to an embodiment of the present invention; Figure 9 This is a diagram showing the rotating bucket wheel and sweeping movement direction of an excavation device according to an embodiment of the present invention; Figure 10 This is a flowchart of a single-site excavation construction process of a ship according to an embodiment of the present invention; Figure 11 This is a schematic diagram of the rotary support of the present invention.

[0014] In the diagram: 1-Side end cover; 2-Outer shell bolt; 3-Bucket; 4-Connector; 5-Outer shell; 6-Storage bin; 7-Inclined screw conveyor; 8-Air inlet 1; 9-Support component; 10-Firming rib; 11-Tap roller bearing; 12-Sleeve 1; 13-Sleeve 2; 14-Locking nut; 15-Hydraulic motor; 16-Bolt 2; 17-Sealing ring 1; 18-Sleeve 3; 19-O-ring 1; 20-Positioning post; 21-Boss structure; 22-O-ring seal Circle 2; 23-Outer shell nut; 24-Screw conveyor; 25-Weighing sensor; 26-Threaded air pipe quick connector; 27-One-way valve; 28-Air inlet 2; 29-Rotating shaft; 30-Turntable; 31-Winding device; 32-Hull; 33-Rotating bucket wheel; 34-Rotating support; 35-Drainage hole; 36-Hinge point 1; 37-Hinge point 2; 38-Hinge point 3; 39-Hinge point 4; 40-Rotating component 1; 41-Rotating component 2; 42-Excavation device. Detailed Implementation

[0015] The present invention will now be described in detail and completely with reference to the accompanying drawings. Those skilled in the art will be able to implement the present invention based on these descriptions. Before describing the present invention with reference to the accompanying drawings, it should be particularly noted that the technical solutions and features provided in various parts of the present invention, including the following description, can be combined with each other without conflict.

[0016] Furthermore, the embodiments of the present invention described below are generally only some, not all, of the embodiments of the present invention. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0017] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The specific implementation process is as follows: like Figure 1 As shown, the present invention provides an underwater foundation excavation device, comprising: a hull 32, a rotating support 34, and an excavation device; The hull 32 serves as the working platform. The hull 32 is connected to the excavation device via a rotating support 34 to ensure the excavation device remains horizontal during lowering or raising. A winch 31 is located at the bow of the hull 32, and its cable is connected to the excavation device to bear most of its weight. Both the winch 31 and the rotating support 34 are equipped with tension sensors. The rotating support is existing technology. In this embodiment, the rotating support 34 includes four sets of rotating components, symmetrically hinged in pairs to both sides of the excavation device, and also located on both sides of the hull 32. Figure 11As shown, taking two sets of rotating parts on one side as an example, rotating part 1 40 and rotating part 2 41 are respectively hinged to the excavation device 42 and the hull. A parallelogram is formed at hinge point 1 36, hinge point 2 37, hinge point 38 and hinge point 4 39. As long as the line connecting hinge point 1 and hinge point 2 is vertically downward, the line connecting hinge point 3 and hinge point 4 is also vertically downward, ensuring the posture of the excavation device.

[0018] The excavation device includes a drainage cover, a hydraulic motor 15, a rotating bucket wheel 33, a storage bin 6, and a screw conveyor 24. The drainage cover includes an outer shell 5 and a side end cover 1. One end of the outer shell 5 and the side end cover 1 are sealed together to form a drainage cover with an opening only at the bottom. A water pressure sensor and a gas pressure sensor are installed on the outside of the drainage cover. In this embodiment, the end of the outer shell 5 is connected to the side end cover 1 by bolts 2 and nuts 23. An O-ring 22 is installed between the side end cover 1 and the outer shell 5. An air inlet 8 is installed on the outside of the side end cover 1. The storage bin 6 is installed inside the side end cover 1. The top of the storage bin 6 is open, and the bottom of the storage bin 6 has a drainage hole 35. 5 can be several, and the aperture is smaller than the soil particle size. A weighing sensor 25 is installed inside the storage bin 6. The other end of the outer shell 5 is a boss structure 21 with mounting holes. A reinforcing rib 10 is provided between the boss structure 21 and the outer shell 5 to improve overall strength. The rotating bucket wheel 33 includes a rotating shaft 29, a turntable 30, and a bucket 3. The disc-shaped turntable 30 is coaxially arranged with the rotating shaft 29. There is a certain gap between the storage bin 6 and the turntable 30. When the turntable 30 rotates, the storage bin 6 remains stationary. A bucket 3 is installed at the circumferential end of the turntable 30. The rotating shaft 29 is installed in the mounting hole via a bearing. In this embodiment, as... Figure 4As shown, two tapered roller bearings 11 are used to install the rotating shaft 29 in the mounting hole. The inner rings of the two tapered roller bearings 11 are limited by sleeve two 13, and the outer rings of the two tapered roller bearings 11 are limited by sleeve one 12. The outer ring of the tapered roller bearing 11 on the side closer to the drain cover is limited by the housing 5. The inner ring of this tapered roller bearing 11 is limited by the boss of the rotating shaft 29. The inner ring of the tapered roller bearing 11 on the side closer to the hydraulic motor 15 is limited by the locking nut 14 screwed to the end of the rotating shaft 29. The outer ring of this tapered roller bearing 11 is limited by the sleeve three 18 set between its outer ring and the boss of the hydraulic motor 15. The rotating shaft 29 is driven to rotate by the hydraulic motor 15. Specifically, the rotating shaft 29 and the hydraulic motor 15 are connected by a key to drive the rotating shaft 29 to rotate. The hydraulic motor 15 is installed on the end face of the mounting hole by bolt 16 and sealing ring 17 to fix the hydraulic motor 15 and seal the end of the hole. An O-ring 1917 is also installed between the rotating shaft 29 and the outer casing 5 to seal the other end of the hole. The mud scooped by the bucket 3 enters the storage bin 6 under the drive of the turntable 30 and is transported to the hull 32 by the screw conveyor 24.

[0019] Compared to the closest existing technologies, such as trailing suction hopper or articulated suction hopper dredgers, these devices are completely exposed to water during excavation, making it impossible to control the mixing of mud and water, resulting in the diffusion of a large amount of fine particulate matter and polluting the surrounding water. In the specific embodiment of this invention, during operation, the excavation device is lowered to the bottom of the water. Sensors detect the water depth and air pressure, injecting high-pressure air into the drainage hood to expel the internal water, creating a locally dry construction zone. The rotating bucket wheel 33 excavates the soil and temporarily stores it in the storage bin 6. Once the weighing sensor 25 detects a certain amount, the screw conveyor 24 is activated to transport the soil. During the process, air pressure control reduces the moisture content of the soil, thereby achieving efficient and environmentally friendly excavation.

[0020] In another technical solution, the bucket 3 is a bidirectional bucket 3, which can dig regardless of whether the hydraulic motor 15 rotates forward or backward. Multiple buckets 3 (e.g., 6) are arranged around the turntable 30. Each bidirectional bucket 3 is composed of two buckets 3 spliced ​​back to back. The top edge of each bucket 3 is serrated to facilitate the excavation of soil. At the bottom of the bucket 3 near the periphery of the turntable 30, the bottom of the bucket 3 is semi-open, that is, the top of the bucket 3 protrudes from the bottom of the bucket 3 in the horizontal direction. When the turntable 30 drives the bucket 3 to rotate to the highest point, the soil falls into the storage bin 6 through the semi-opening at the bottom of the bucket 3 under the action of gravity.

[0021] Compared to the closest existing technology, such as ordinary unidirectional buckets 3, these buckets 3 cannot effectively dig soil when reversing, and their simple structure makes them prone to mud jamming or incomplete unloading. In a specific embodiment of the present invention, the buckets 3 are bidirectional buckets 3, with multiple buckets arranged circumferentially along the turntable 30. Each bidirectional bucket 3 is composed of two buckets 3 spliced ​​back-to-back. The top edge of the bucket 3 is serrated to enhance cutting ability, and the bottom is semi-open to facilitate the natural shedding of soil under gravity. During excavation, regardless of whether the hydraulic motor 15 rotates forward or backward, the bidirectional buckets 3 can continuously dig soil and bring it into the storage bin 6. When the turntable 30 rotates to its highest point, the semi-open bottom allows soil to fall smoothly into the storage bin 6, avoiding accumulation. This design not only improves excavation coverage but also reduces the risk of bucket 3 blockage, adapts to the reciprocating motion during ship-based sweeping excavation, and significantly improves construction efficiency and adaptability.

[0022] In another technical solution, the bucket 3 is fixed to the turntable 30 via a connector 4 and a support 9. The support 9 supports the bucket 3. The support 9 is positioned relative to the turntable 30, and the turntable 30 and the support 9 are connected by the connector 4. Both sides of the bucket 3 are fixed to the turntable 30 and the support 9 respectively. The connector 4 is positioned between the two buckets 3, ensuring that while supporting the bidirectional bucket 3, the semi-open bottom of the bidirectional bucket 3 allows soil to fall downwards under gravity when it rotates to a higher position, without interfering with the soil falling into the storage bin 6. This layout not only distributes the load during excavation but also prevents the bucket 3 from interfering with the storage bin 6 or other components during rotation. The support 9 and the connector 4 together form a stable frame, ensuring the bucket 3 remains stable during both forward and reverse rotation. The semi-open bottom design ensures that soil falls smoothly into the storage bin 6 under gravity without additional power assistance. This structure improves the durability and continuity of excavation, reduces maintenance requirements, and is suitable for long-term underwater operations.

[0023] like Figures 2-3 As shown, the storage compartment 6 is an arc-shaped structure with an opening at the top. It is located in the cavity formed by the connector 4, the support 9 and the turntable 30, and the storage compartment 6 does not contact these components. The storage compartment 6 is fixed by the side end cover 1.

[0024] In another technical solution, such as Figure 5 As shown, the screw conveyor 24 includes an inclined screw conveyor 247 and a vertical screw conveyor 24; An inclined screw conveyor 247 is installed through the side end cover 1. The inclined screw conveyor 247 extends into the storage bin 6 through the opening on the side end cover 1. The screw part of the inclined screw conveyor 247 is driven by a rotary motor. A vertical screw conveyor 24 is installed at the end of the inclined screw close to the rotary motor. The screw part of the vertical screw conveyor 24 is driven by a rotary motor. The mud in the storage bin 6 can be transported to the ship through the inclined screw conveyor 247 and the vertical screw conveyor 24.

[0025] In another technical solution, such as Figure 6 As shown, several air inlets 28 are installed between the inclined screw conveyor 247 and the vertical screw conveyor 24, and on the vertical screw. Each air inlet 28 is equipped with a one-way valve 27 via a threaded air pipe quick-connect 26. After the rotating bucket wheel 33 dredges the mud, it is poured into the storage bin 6. By injecting high-pressure air into the air inlet 8, the water in the drainage hood can be drained when it is underwater, and the water in the mud in the storage bin 6 can be squeezed out through the drainage hole 35. By injecting high-pressure air into the air inlet 28, the water in the mud conveyed by the screw is further squeezed out through the multi-stage extrusion of multiple air inlets 28, reducing the moisture content of the excavated soil. The one-way valve 27 ensures that the conveyed mud does not enter the air pipe. When the screw conveyor 24 is started and conveys the mud, high-pressure air is injected into the conveying pipeline through these air inlets 28. High-pressure air penetrates the soil, separating the free water. The squeezed-out water flows back along the pipe under gravity and is eventually discharged through the drain hole 35 at the bottom of the storage chamber 6. The key function of the one-way valve 27 is to prevent wet mud or sewage from flowing back into the air intake pipe during pressure fluctuations, thus ensuring the smooth flow of air and the reliable operation of the system. This multi-point air injection dehydration method achieves secondary dehydration of the soil during transportation, resulting in more compacted soil and significantly reducing the load on subsequent processing.

[0026] In another technical solution, such as Figure 7 As shown, it also includes an intake system, which includes an air compressor, pipes, valves, etc. The air compressor's outlet pipes are mainly divided into two branches, forming the first branch and the second branch. The first branch is equipped with valve one, connected to a four-way connector one. The other three branches of the four-way connector one are connected to exhaust valve one, pressure gauge one, and inlet pipe one, respectively. Inlet pipe one is connected to inlet port one (8). The second branch is equipped with valve two, connected to a four-way connector two. The other three branches of the four-way connector two are connected to exhaust valve two, pressure gauge two, and inlet port two (28), respectively. Valve three is installed in the pipe between inlet port two (28) and the four-way connector two to control the opening and closing of inlet port two (28). If there are multiple inlet ports two (28), a four-way connector three can be installed on one of the four-way connector two branches and connected to inlet port two (28) or pressure gauge two. This expansion can be achieved by connecting multiple four-way connectors. In addition, valves are installed on the intake pipes between the inclined and vertical spirals, and on several intake pipes on the vertical spiral, to individually control the intake of each inlet port two (28), such as valves three, four, and five. This dual-path, independently controllable air supply system allows the air pressure maintenance of the drainage hood and the dehydration and air injection during the transportation process to proceed without interference. The pressure gauge provides real-time monitoring, and the exhaust valve ensures safe pressure relief, thereby guaranteeing the stability, safety, and efficiency of the pneumatic control process throughout the excavation operation.

[0027] This invention also provides a method for underwater foundation excavation, such as... Figures 8-10 As shown, it includes the following steps: S1: Start working. The excavation device is lowered to the bottom of the water by the rotating support 34 of the hull 32 and the winch device 31. During the descent, the height h1 of the bottom of the drainage hood from the water surface is detected by the water pressure sensor, and the air pressure P inside the drainage hood is detected by the air pressure sensor. The air intake of the air inlet 8 is controlled until the air pressure P reaches the requirement: P=ρgh1. Then the valve is closed. S2: During descent, the load weight is detected by the tension sensor installed on the winch device 31 and the support device. When the load decreases significantly during underwater descent, the excavation device reaches the mud surface. S3: The rotating bucket wheel 33 rotates to begin digging, excavating the soil below the entire drainage hood and pouring the excavated soil into the storage bin 6. When the weighing sensor 25 of the storage bin 6 detects that the soil in the storage bin 6 has reached a certain amount (which can be set), the screw conveyor 24 is activated to transport the soil to the ship. During the soil transport process, valves two and three are opened, and high-pressure air is introduced along the soil transport path to squeeze out the water from the soil. After recirculation, the water is discharged through the drainage hole 35 at the bottom of the storage bin 6, achieving dry treatment of the excavated soil. In this embodiment, as... Figure 7As shown, there are three air inlets 28, so four valves are set. Therefore, during the soil conveying process, in addition to opening valve 2, valves 3, 4 and 5 also need to be opened. The pressure of the input gas is detected by pressure gauge 2. When it is necessary to reduce the air pressure, valve 2 is closed and valves 3 and 2 are opened to discharge the air in the screw conveyor 24. The pressure is detected by pressure gauge 2. S4: During the dredging process, the ship rotates around the positioning pile 20 to achieve sweeping dredging at the current position. After one layer of soil is excavated, the dredging device is gradually lowered through the rotating support 34 and the winch device 31, and then sweeping dredging is carried out along the previous sweeping path. In this way, the sweeping dredging is repeated and the excavation is continuously deepened. During this process, the rotating bucket wheel 33 reverses. S5: When the vessel is changing position, the excavation device needs to float up. Set the floatation height H. At this time, the drainage cover is depressurized by releasing air. Adjust the air pressure inside the drainage cover by keeping valve one closed and opening exhaust valve one to release the air inside the drainage cover and reduce the air pressure to adapt to different underwater depths of the drainage cover. S6: After the vessel is moved, the excavation device will submerge again, and the construction will be repeated in this cycle.

[0028] The above construction method seamlessly integrates sensor monitoring, air pressure control, mechanical excavation, online dehydration, and ship positioning and movement, forming an automated and cyclical high-efficiency construction process that significantly improves the quality of operation and the level of environmental protection.

[0029] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and embodiments shown and described herein.

Claims

1. An excavation method using an underwater foundation excavation device, characterized in that, Underwater foundation excavation equipment includes: hull, rotating support, and excavation device; The hull and the excavation device are connected by a swivel support to ensure that the excavation device remains horizontal when it is lowered or raised; a winch is provided at the bow of the hull, and the cable of the winch is connected to the excavation device; tension sensors are installed on both the winch and the swivel support. The excavation device includes a drainage hood, a hydraulic motor, a rotating bucket wheel, a storage bin, and a screw conveyor. The drainage hood consists of an outer shell and a side end cover. One end of the outer shell and the side end cover are sealed together to form a drainage hood with an opening only at the bottom. A water pressure sensor and a gas pressure sensor are installed on the outside of the drainage hood. An air inlet is installed on the outside of the side end cover. The storage bin is installed inside the side end cover. The top of the storage bin is open, and a drainage hole is opened at the bottom of the storage bin. A weighing sensor is installed inside the storage bin. The other end of the outer shell is a boss structure with mounting holes. The rotating bucket wheel includes a rotating shaft, a turntable, and a bucket. The disc-shaped turntable is coaxially arranged with the rotating shaft. There is a certain gap between the storage bin and the turntable. A bucket is installed at the circumferential end of the turntable. The rotating shaft is installed in the mounting hole through a bearing and is driven to rotate by a hydraulic motor. The mud excavated by the bucket enters the storage bin under the drive of the turntable and is transported to the hull by the screw conveyor. The spiral conveying device includes an inclined spiral conveying device and a vertical spiral conveying device; several air inlets are installed between the inclined spiral conveying device and the vertical spiral conveying device and on the vertical spiral, and each air inlet is equipped with a one-way valve. It also includes the air intake system, which includes an air compressor, pipes, and valves; The air pipes from the air compressor form a first branch pipe and a second branch pipe. The first branch pipe is equipped with valve one, which is connected to a four-way valve one. The other three ends of the four-way valve one are connected to exhaust valve one, pressure gauge one, and air inlet pipe one, respectively. Air inlet pipe one is connected to air inlet one. The second branch pipe is equipped with valve two, which is connected to a four-way valve two. The other three ends of the four-way valve two are connected to exhaust valve two, pressure gauge two, and air inlet two, respectively. A valve three is installed in the pipe between air inlet two and four-way valve two to control the opening and closing of air inlet two. The excavation method includes the following steps: S1: The excavation device is lowered to the bottom of the water by the rotation support of the hull and the winch device. During the descent, the height h1 of the bottom of the drainage hood from the water surface is detected by the water pressure sensor, and the air pressure P inside the drainage hood is detected by the air pressure sensor. The air intake of the first air inlet is controlled until the air pressure P reaches the requirement: P=ρgh1, and then the first valve is closed. S2: During descent, the load weight is detected by the tension sensors installed on the winch and support devices. When the load decreases significantly during underwater descent, the excavation device reaches the mud surface. S3: The rotating bucket wheel rotates and begins to dig soil, excavating the soil below the entire drainage hood and pouring the excavated soil into the storage bin. When the soil in the storage bin reaches a certain amount, the screw conveyor is activated to transport the soil to the ship. During the soil conveying process, valves two and three are opened, and high-pressure air is introduced along the conveying path to squeeze out the water in the soil. After reflux, the water is discharged through the drainage hole at the bottom of the storage bin. When it is necessary to reduce the air pressure, valve two is closed, and valve three and exhaust valve two are opened to discharge the air in the screw conveyor. S4: During the dredging process, the ship rotates around the positioning pile to achieve sweeping dredging at the current position. After one layer of soil is excavated, the dredging device is gradually lowered through the rotating support and winch device, and then sweeping dredging is carried out along the previous sweeping path. In this way, the sweeping dredging is repeated and the excavation is continuously deepened. During this process, the rotating bucket wheel reverses. S5: When the vessel is being moved, the excavation device needs to float. Set the floatation height H. At this time, the drainage cover is depressurized by releasing air and adjusting the air pressure inside the drainage cover. S6: After the vessel is moved, the excavation device will submerge again, and the construction will be repeated in this cycle.

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