Submarine cable laying active backfilling device and method

Abstract

The invention belongs to the technical field of underwater operation, and particularly relates to a seabed cable laying active backfilling device and method.The seabed cable laying active backfilling device comprises a backfilling module, the backfilling module comprises a first backfilling pipeline and a second backfilling pipeline, and the first backfilling pipeline is provided with a first spraying nozzle facing the surface of a seabed in a communicating mode; a first spraying nozzle is arranged on the backfilling pipeline and inclines downwards in the direction of the lower end of the second backfilling pipeline, a second spraying nozzle used for facing the inner side wall of the sea ditch is arranged on the second backfilling pipeline in a communicating mode, and the second spraying nozzle is arranged at the bottom of the lower end of the second backfilling pipeline and inclines upwards in the direction of the first backfilling pipeline. The spraying directions of the first spraying nozzle and the second spraying nozzle are opposite, the first spraying nozzle and the second spraying nozzle jointly form hedging jet flow, and for a seabed with high soil hardness and large viscosity, the hedging jet flow can effectively thrust off soil located between the inner side wall of a sea ditch and the surface of the seabed, make the soil loose and fall off to be backfilled into the sea ditch, bury cables and achieve active backfilling.

Description

Technical Field

[0001] The invention belongs to the technical field of underwater operations, and in particular relates to an active backfilling device and method for submarine cable laying. Background Art

[0002] When setting cables on the seabed, in order to ensure the safety and stability of the cables and avoid damage caused by waves, marine life, anchors and other factors, trenching and cable burying operations are required. First, a trench of a certain depth and width is opened on the seabed through a trenching device, and then the cables are laid in the trench, buried to a corresponding depth, and the cables are buried to avoid being exposed. For seabeds with soft soil or muddy texture, after the cables sink to the bottom of the trench, the mud on the surface of the seabed can be quickly backfilled into the trench to bury the cables under the action of natural scouring by ocean currents. However, for seabeds with high soil hardness and high viscosity, it is not easy to collapse under the action of ocean currents, and the viscosity between the soils is large, and it is not easy to loosen and fall off. Therefore, it is difficult to naturally backfill into the trench with the scouring of ocean currents within a period of time, resulting in the cables being exposed for a long time, posing a safety hazard. In order to speed up backfilling, some backfilling devices are provided in the prior art, such as the spray-flushing backfilling integrated machine provided by application number CN202111197341.9, which backfills the soil by means of a spray jet. However, it can be seen from the attached drawings that the nozzle is specifically located above the seabed, and sprays a jet from top to bottom toward the inside of the trench. This backfilling method is only applicable to soft and easily collapsed soil. When the soil is hard and sticky, the soil is not easy to fall off and the soil will stick to each other. It will loosen under the action of the jet, but the soil is not easy to disconnect directly, and the soil cannot be effectively flushed to loosen it and backfill it into the trench. Therefore, the problem of exposed cables still occurs. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide an active backfill device and method for submarine cable laying that is applicable to seabeds with high soil hardness and high viscosity, and can effectively break the soil of this nature, causing it to loosen and fall back into the trench to bury cables.

[0004] The present invention provides an active backfilling device for submarine cable laying, comprising a backfilling module, wherein the backfilling module comprises a backfilling pipeline 1 and a backfilling pipeline 2, wherein the backfilling pipeline 2 is arranged downward relative to the backfilling pipeline 1 and is used to extend into a trench, wherein two backfilling modules are provided, and a gap is provided between the backfilling pipelines 2 in the two backfilling modules for the cables to pass through, and the backfilling pipeline 1 in a single backfilling module is located on a side of the backfilling pipeline 2 away from the other backfilling module; In a single backfill module, both the first backfill pipeline and the second backfill pipeline are connected to the water inlet end. A first spray nozzle for facing the seabed surface is connected to the first backfill pipeline. The first spray nozzle is arranged to incline downward in the direction of the lower end of the second backfill pipeline. A second spray nozzle for facing the inner sidewall of the trench is connected to the second backfill pipeline. The second spray nozzle is arranged at the bottom of the lower end of the second backfill pipeline and inclines upward in the direction of the first backfill pipeline. There is a gap between the first spray nozzle and the second spray nozzle, and their spray directions are opposite to each other.

[0005] Further, the inclination angle of the second spray nozzle relative to the lower end of the second backfill pipeline is less than 45°.

[0006] Further, it further includes two deployment mechanisms and two fixing brackets for connecting to the fuselage main body of the underwater operation system. The two backfill modules are correspondingly arranged on the two fixing brackets to be supported by the two fixing brackets. The two deployment mechanisms are used to correspondingly drive the deployment and recovery of the two backfill modules.

[0007] Further, in a single backfill module, the first backfill pipeline is connected and conducted with the second backfill pipeline. The first backfill pipeline is horizontally arranged relative to the second backfill pipeline. The water inlet end is arranged on the first backfill pipeline or the second backfill pipeline.

[0008] Further, the connection between the second backfill pipeline and the first backfill pipeline is detachable.

[0009] Further, when the two deployment mechanisms drive the deployment and recovery of the two backfill modules, they drive the two backfill modules to rotate. Support holes are provided on the two fixing brackets. The first backfill pipeline is passed through the corresponding support hole and can rotate in the corresponding support hole.

[0010] Further, an adjustment mechanism one is provided on the corresponding fixing bracket of a single backfill module, which is used to drive the first backfill pipeline in the backfill module to move axially along the support hole, so as to adjust the distance between the second backfill pipelines in the two backfill modules.

[0011] Further, the first backfill pipeline and / or the second backfill pipeline is a telescopic pipeline, and an adjustment mechanism two is correspondingly provided, which is used to drive the first backfill pipeline to expand and contract to adjust the distance between the first spray nozzle and the second backfill pipeline and / or drive the second backfill pipeline to expand and contract to adjust the distance between the second spray nozzle and the first backfill pipeline.

[0012] Further, the telescopic pipeline includes two pipelines connected by a dynamic seal. The adjustment mechanism two drives one of the pipelines to move axially along the other pipeline to perform expansion and contraction.

[0013] The content of the present invention also provides a method for active backfilling of submarine cable laying, which uses the submarine cable laying active backfilling device as described above. The method includes the following steps: S1. Lower the lower ends of the second backfill pipelines in the two backfill modules into the trench and place them on both sides of the cable correspondingly. The first jet nozzle is inclined downward towards the seabed surface in the direction of the trench above the seabed, and the second jet nozzle is inclined upward towards the inner side wall of the trench at the bottom of the trench; S2. The jets ejected from the first jet nozzle and the second jet nozzle form an impact jet, breaking the soil between the inner side wall of the trench and the seabed surface, making it loose and collapsing into the trench for backfilling to bury the cable.

[0014] The beneficial effects of the present invention are as follows. The second jet nozzle at the bottom of the lower end of the second backfill pipeline is located at the bottom of the trench in the trench, and it ejects a jet obliquely upward from the bottom towards the inner side wall of the trench. At the same time, the first jet nozzle on the first backfill pipeline ejects a jet obliquely downward towards the seabed surface. The two together form an impact jet. For the seabed with high soil hardness and large viscosity, this impact jet can effectively break the soil between the inner side wall of the trench and the seabed surface, make the soil loose and fall off and backfill into the trench to bury the cable, quickly carry out active backfilling, avoid potential safety hazards caused by long-term exposure of the cable, and improve the operation efficiency and quality. And the setting of the above impact jet can reduce the single-side jet water pressure requirements of the first jet nozzle and the second jet nozzle on the premise of ensuring that the soil between the inner side wall of the trench and the seabed surface is broken, thereby reducing the pressure requirements on the pipeline. Compared with the mechanical soil cutting method, the impact jet of the present invention can reduce the damage to the cable while meeting the backfill requirements. In addition, for the seabed with softer soil, the present invention can, after the cable falls into the trench, use the impact jet to accelerate the collapse speed of the soil on both sides of the trench, make it backfill more quickly, and completely bury the cable in a shorter time, improving the operation efficiency and quality. Description of the Drawings

[0015] Figure 1 It is a layout diagram of the present invention with an increased distance between the two backfill modules.

[0016] Figure 2 It is a layout diagram of the present invention with a reduced distance between the two backfill modules.

[0017] Figure 3 It is a recovery diagram of the present invention when the two backfill modules are far apart.

[0018] Figure 4 It is a first perspective structural diagram of a single backfill module of the present invention.

[0019] Figure 5 For the present invention Figure 4 A-A cross-sectional view in the present invention.

[0020] Figure 6 It is a schematic structural diagram of a single backfill module from a second perspective of the present invention.

[0021] Figure 7 It is a schematic diagram of the working status of two backfill modules of the present invention.

[0022] In the figure: 1. Backfill pipeline 1; 2. Backfill pipeline 2; 3. Spray nozzle 1; 4. Spray nozzle 2; 5. Water inlet end; 6. Fixed bracket; 7. Laying mechanism; 71. Mounting frame; 72. Driving member; 73. Connecting arm 1; 74. Connecting arm 2; 75. Connecting arm 3; 76. Guide column; 8. Adjustment mechanism 1; 100. Cable; 200. Seabed. DETAILED DESCRIPTION

[0023] like Figures 1-7 As shown, the present invention provides an active backfilling device for submarine cable laying, which is used to backfill the trench and bury the cable 100 after the cable 100 is laid to the bottom of the trench. The active backfilling device for submarine cable laying includes a backfilling module, which includes a backfilling pipeline 1 and a backfilling pipeline 2. The backfilling pipeline 2 is vertically arranged downward relative to the backfilling pipeline 1, and the lower end of the backfilling pipeline 2 is used to extend into the trench for operation. There are two backfilling modules, and there is a gap between the backfilling pipelines 2 in the two backfilling modules for the cable 100 to pass through, that is, when the two backfilling modules are in operation, the two backfilling pipelines 2 are located on both sides of the cable 10, and the backfilling pipeline 1 in a single backfilling module is located on the side of the backfilling pipeline 2 away from the other backfilling module.

[0024] In a single backfill module, both the backfill pipeline 1 and the backfill pipeline 2 are connected to the water inlet 5, and the water inlet 5 is used to connect to an external water supply unit, such as a high-pressure water pump, to supply water to the backfill pipeline 1 and the backfill pipeline 2. The backfill pipeline 1 is connected to a jet nozzle 3 for facing the surface of the seabed 200. The jet nozzle 3 is arranged on the backfill pipeline 1 and is tilted downward in the direction where the lower end of the backfill pipeline 2 is located. The backfill pipeline 2 is connected to a jet nozzle 24 for facing the inner wall of the trench. The jet nozzle 24 is arranged at the bottom of the lower end of the backfill pipeline 2 and is arranged on the backfill pipeline 2 and is tilted upward in the direction where the backfill pipeline 1 is located. There is a gap between the jet nozzle 1 and the jet nozzle 2, which is used to accommodate the area from the inner wall of the trench to the surface of the seabed 200, and the jet nozzle 1 and the jet nozzle 2 are arranged in opposite directions to form a counter-jet. The backfill pipeline 1 and the backfill pipeline 2 serve as supporting structures of the spray nozzle 1 3 and the spray nozzle 2 4, and also serve as water supply pipelines of the spray nozzle 1 3 and the spray nozzle 2 4.

[0025] The active backfilling device provided by the present invention is used as follows Figure 7As shown in the figure, the lower ends of the second backfill pipelines 2 in the two backfill modules both extend into the trench, and the two second backfill pipelines 2 are correspondingly located on both sides of the cable 100, and the two first backfill pipelines 1 are correspondingly located above the seabed 200 outside both sides of the trench. The jet nozzles two 4 at the bottom of the lower ends of the second backfill pipelines 2 are located at the bottom of the trench in the trench, and jet out jets obliquely upward from the bottom towards the inner side wall of the trench. At the same time, the jet nozzles one 3 on the first backfill pipelines 1 jet out jets obliquely downward towards the surface of the seabed 200. The two together form a counter-jet. For the seabed 200 with high soil hardness and large viscosity, the counter-jet can effectively break the soil between the inner side wall of the trench and the surface of the seabed 200, and make the soil loose and fall off and backfill into the trench, burying the cable 100, and quickly carrying out active backfill to avoid the safety hazards caused by the cable 100 being exposed for a long time. And the setting of the above counter-jet can reduce the single-side jet water pressure requirements of the jet nozzles one 3 and the jet nozzles two 4 on the premise of ensuring that the soil between the inner side wall of the trench and the surface of the seabed 200 is broken, thereby reducing the pressure requirements on the pipelines. In addition, for the softer seabed 200, the present invention can, after the cable 200 falls into the trench, use the counter-jet to accelerate the collapse speed of the soil on both sides of the trench, make it backfill more quickly, and completely bury the cable 100 in a shorter time, improving the operation efficiency and operation quality.

[0026] In the present invention, the lower end of the second backfill pipeline 2 is vertically arranged, and the inclination angle of the jet nozzle two 4 relative to the lower end of the second backfill pipeline 2 is less than 45°, so that the included angle between the jet ejected by the jet nozzle two 4 during operation and the plumb direction is less than 45°. Since the jetting directions of the jet nozzle one 3 and the jet nozzle two 4 are relatively arranged, the included angle between the jet ejected by the jet nozzle one 3 during operation and the horizontal direction is greater than 45°. This arrangement can make the action position of the jet ejected obliquely upward by the jet nozzle two 4 in the middle and upper part regions of the inner side arm of the trench, and make the action position of the jet ejected obliquely downward by the jet nozzle one 3 on the surface of the seabed 200 close to the trench. Furthermore, the distance between the action positions of the two counter-jets is short. On the basis of meeting the requirements of breaking the soil and backfilling and burying the cable 100, the soil-breaking difficulty is reduced and the soil-breaking efficiency is improved.

[0027] The present invention further includes two placing mechanisms 7 and two fixing brackets 6 for connecting with the fuselage main body of the underwater operation system. The two backfill modules are correspondingly arranged on the two fixing brackets 6 to be supported by the two fixing brackets 6. The two placing mechanisms 7 are used to correspondingly drive the placing and recovery of the two backfill modules. As Figure 1 and Figure 2 shown, it is a state schematic diagram after the two backfill modules are placed. As Figure 3 shown, it is a state schematic diagram after the two backfill modules are recovered. Among them, the placing mentioned in this article refers to lowering the target mechanism to the working posture.

[0028] In a single backfill module, the first backfill pipeline 1 is connected and communicated with the second backfill pipeline 2. The first backfill pipeline 1 is horizontally arranged relative to the second backfill pipeline 2, specifically extending in a direction away from another backfill module relative to the second backfill pipeline 2. The water inlet end 5 is arranged on the first backfill pipeline 1 or the second backfill pipeline 2. In this setting mode, the first backfill pipeline 1 and the second backfill pipeline 2 are connected to each other and supplied with water through the same water inlet end 5. The water inlet end 5 is specifically arranged at one end of the first backfill pipeline 1 away from the second backfill pipeline 2.

[0029] In an embodiment of the present invention, the connection between the second backfill pipeline 2 and the first backfill pipeline 1 is detachable, for example, by flange connection. In this embodiment, different lengths of the second backfill pipeline 2 can be pre-replaced on the deck of the ship according to the requirements of the trenching depth for cable 100 laying, so as to adapt to the corresponding depth of the trench for soil backfilling, broaden the applicable range and improve the use flexibility.

[0030] Based on the above embodiment, when the two deployment mechanisms 7 drive the two backfill modules to be deployed and recovered, they drive the two backfill modules to rotate. A support hole is arranged on the fixed bracket 6, and the first backfill pipeline 1 is passed through the corresponding support hole, and the first backfill pipeline 1 can rotate in the corresponding support hole. This support hole is used to support the first backfill pipeline 1 and support the backfill module on the basis of meeting the rotational deployment and recovery of the backfill module.

[0031] Specifically, the deployment mechanism 7 includes an installation frame 71, a driving member 72 and a connecting arm structure. A positioning hole is also arranged on the fixed bracket 6. The first backfill pipeline 1 is passed through the installation frame 71, that is, the first backfill pipeline 1 is passed through both the fixed bracket 6 and the installation frame 71 at the same time, and is supported jointly by the fixed bracket 6 and the installation frame 71 to improve the reliability of the support. The connecting arm structure includes a first connecting arm 73, a second connecting arm 74 and a third connecting arm 75. The driving member 72 is specifically an oil cylinder, and its cylinder end is hinged on the installation frame. One end of the first connecting arm 73 is fixed to the first backfill pipeline 1, and the other end is hinged to one end of the second connecting arm 74. The other end of the second connecting arm 74 is hinged to one end of the third connecting arm 75 and the piston end of the driving member 72, and the third connecting arm 75 is bent, and the other end is hinged to the installation frame 75, forming a connection structure as shown in Figure 5 When the piston end of the driving member 72 expands and contracts, the first backfill pipeline 1 is driven to rotate through the connecting arm structure, so as to drive the overall turning of the backfill module to realize deployment and recovery. Compared with the linear lifting structure, the method of flipping deployment and recovery has a smaller stroke requirement for the driving member 72, the volume of the driving member 72 can be smaller, and at the same time, compared with the motor driving method, the stability of the oil cylinder cooperating with the connecting arm structure for driving is better and the load-bearing capacity is stronger.

[0032] In this embodiment, the first backfill pipeline 1 can rotate within the support hole and also move axially within the support hole. An adjusting mechanism 8 is provided on the corresponding fixed bracket 6 of a single backfill module to drive the first backfill pipeline 1 in the backfill module to move axially along the support hole, so as to adjust the distance between the second backfill pipelines 2 in two backfill modules, thereby adapting to trenches of different widths, broadening the applicable range and improving the use flexibility. In the above-mentioned laying mechanism 7, due to the connection between the driving member 72 and the connecting arm structure, the first backfill pipeline 1 can rotate around the mounting frame 71 but cannot move axially, that is, in the axial direction, the first backfill pipeline 1 and the mounting frame 71 move synchronously. A guide post 76 is provided on the mounting frame 71, and the guide post 76 is horizontally inserted into the positioning hole. The mounting frame 71 is supported through the cooperation of the positioning hole and the guide post 76. The adjusting mechanism 8 is specifically an oil cylinder. One end of the cylinder body end and the piston end of the oil cylinder is connected to the fixed bracket 6, and the other end is connected to the mounting frame 71. The mounting frame 71 is driven by the adjusting mechanism 8 and drives the first backfill pipeline 1 to move axially along the fixed bracket 6, so as to adjust the distance between the two second backfill pipelines 2, that is, as Figure 1 and Figure 2 shown.

[0033] In another embodiment of the present invention, the first backfill pipeline 1 and / or the second backfill pipeline 2 is a telescopic pipeline, and an adjusting mechanism 2 is correspondingly provided to drive the first backfill pipeline 1 to expand and contract to adjust the distance between the first spray nozzle 3 and the second backfill pipeline 2 and / or drive the second backfill pipeline 2 to expand and contract to adjust the distance between the second spray nozzle 4 and the first backfill pipeline 1, so as to adapt to trenches of different sizes, broaden the applicable range and improve the use flexibility. Among them, in this embodiment, the first backfill pipeline 1 and the second backfill pipeline 2 can both be telescopic pipelines and are both provided with an adjusting mechanism 2; or one of the first backfill pipeline 1 and the second backfill pipeline 2 is a telescopic pipeline, and the adjusting mechanism 2 is provided on the telescopic pipeline. When only one of them is a telescopic pipeline, it is preferably the first backfill pipeline 1 that is a telescopic pipeline, and the second backfill pipeline 2 is detachably connected to the first backfill pipeline 1 to facilitate the replacement of backfill pipelines 2 of different lengths and adapt to the telescopic first backfill pipeline 1 to ensure that the spray directions of the first nozzle 3 and the second nozzle 4 are opposite to each other.

[0034] The above-mentioned telescopic pipeline includes two pipelines connected by a dynamic seal. The adjusting mechanism II is specifically an oil cylinder, which is used to drive one pipeline to axially move along the other pipeline for telescoping. In this embodiment, the first backfill pipeline 1 can only rotate in the support hole but cannot axially move in the support hole. Specifically, one of the pipelines in the first backfill pipeline 1 is rotatably arranged in the support hole and axially limited, and the other pipeline in the first backfill pipeline 1 passes through the mounting frame 71. One end of the first connecting arm 73 is specifically fixed to the pipeline passing through the mounting frame 71. The cylinder end of the adjusting mechanism II is connected to the fixed bracket 6 or one of the pipelines, and the piston end is connected to the mounting frame 71 or the other pipeline, so as to realize the telescoping of the first backfill pipeline 1. This setting method can adjust the distance between the two backfill modules while keeping the position of the water inlet end 5 unchanged, and reduce the connection requirements for the water inlet end 5. Among them, when the second backfill pipeline 2 is also a telescopic pipeline, the cylinder end of the adjusting mechanism II is arranged on one of the pipelines of the second backfill pipeline 2, and the piston end is arranged on the other pipeline of the second backfill pipeline 2.

[0035] The present invention also provides a method for active backfill of submarine cable laying, which uses the above-mentioned submarine cable laying active backfill device and includes the following steps: S1. Drive the two backfill modules to turn downward through the two laying mechanisms 7, so that the lower ends of the second backfill pipelines 2 in the two backfill modules extend into the trench and are respectively located on both sides of the cable 100. The first spray nozzle 3 is inclined downward along the direction of the trench above the seabed 200 towards the surface of the seabed 200, and the second spray nozzle 4 is inclined upward at the bottom of the trench towards the inner side wall of the trench; S2. The first spray nozzle 3 sprays a jet downward, and at the same time, the second spray nozzle 4 sprays a jet obliquely upward from bottom to top, jointly forming an impact jet to break the soil from the inner side wall of the trench to the surface of the seabed 200, making it loose and collapse into the trench for backfill to bury the cable 100.

[0036] This active backfill method can be well applied to the seabed 200 with high soil hardness and large viscosity. The impact jet is used to effectively break the soil between the inner side wall of the trench and the surface of the seabed 200, ensuring that the soil can be loosened and collapsed into the trench to bury the cable 100. Under the condition of ensuring that the soil between the inner side wall of the trench and the surface of the seabed 200 is broken, the single-side jet water pressure requirements of the first spray nozzle 3 and the second spray nozzle 4 can be reduced, thereby reducing the pressure requirements for the pipeline. Compared with the mechanical soil cutting method, the impact jet of the present invention can reduce the damage to the cable 100 while meeting the backfill requirements. Those of ordinary skill in the art should understand that the discussion of any of the above embodiments is only exemplary and is not intended to imply that the scope of protection of this application is limited to these examples; under the concept of this application, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations in different aspects of one or more embodiments of this application as described above, and for the sake of brevity, they are not provided in detail.

[0037] One or more embodiments of this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of this application. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of one or more embodiments of this application shall be included within the scope of protection of this application.

Claims

1. An active backfilling device for submarine cable laying, characterized in that, The invention comprises a backfill module, the backfill module comprising a backfill pipeline 1 (1) and a backfill pipeline 2 (2), the backfill pipeline 2 (2) being arranged downward relative to the backfill pipeline 1 (1) and being used to extend into the trench, two backfill modules are provided, a gap is provided between the backfill pipelines 2 (2) in the two backfill modules for the cable (100) to pass through, and the backfill pipeline 1 (1) in a single backfill module is located on a side of the backfill pipeline 2 (2) facing away from the other backfill module; In a single backfill module, both backfill pipeline 1 (1) and backfill pipeline 2 (2) are connected to the water inlet end (5), and backfill pipeline 1 (1) is connected to a spray nozzle 1 (3) for facing the surface of the seabed (200), and spray nozzle 1 (3) is arranged downwardly and tilted in the direction where the lower end of backfill pipeline 2 (2) is located. Backfill pipeline 2 (2) is connected to a spray nozzle 2 (4) for facing the inner wall of the trench, and spray nozzle 2 (4) is arranged at the bottom of the lower end of backfill pipeline 2 (2) and tilted upward in the direction where backfill pipeline 1 (1) is located. There is a gap between spray nozzle 1 (3) and spray nozzle 2 (4), and the spraying directions of the two are arranged relative to each other.

2. The active backfilling device for submarine cable laying according to claim 1, characterized in that, The inclination angle of the second spray nozzle (4) relative to the lower end of the second backfill pipeline (2) is less than 45°.

3. The active backfilling device for submarine cable laying according to claim 1 or 2, characterized in that, It also includes two deployment mechanisms (7) and two fixed brackets (6) for connecting to the main body of the underwater operation system. The two backfill modules are correspondingly arranged on the two fixed brackets (6) so as to be supported by the two fixed brackets (6). The two deployment mechanisms (7) are used to correspondingly drive the deployment and recovery of the two backfill modules.

4. The active backfilling device for submarine cable laying according to claim 3, characterized in that, single In the backfill module, the backfill pipeline one (1) and the backfill pipeline two (2) are connected and conducted, the backfill pipeline one (1) is arranged transversely relative to the backfill pipeline two (2), and the water inlet end (5) is arranged on the backfill pipeline one (1) or the backfill pipeline two (2).

5. The active backfilling device for submarine cable laying according to claim 4, characterized in that, The backfill pipeline 2 (2) and the backfill pipeline 1 (1) are detachably connected.

6. The active backfilling device for submarine cable laying according to claim 3 or 4, characterized in that, When the two deployment mechanisms (7) drive the two backfill modules to be deployed and recovered, they are used to drive the two backfill modules to rotate. The two fixed brackets (6) are provided with support holes, and the backfill pipeline (1) is inserted into the corresponding support holes and can rotate in the corresponding support holes.

7. The active backfilling device for submarine cable laying according to claim 6, characterized in that, An adjustment mechanism (8) is provided on the fixed bracket (6) corresponding to a single backfill module, for driving the backfill pipeline (1) in the backfill module to move axially along the support hole, so as to adjust the distance between the backfill pipelines (2) in the two backfill modules.

8. The active backfilling device for submarine cable laying according to claim 6, characterized in that, The backfill pipeline one (1) and / or the backfill pipeline two (2) are retractable pipelines, and are correspondingly provided with an adjustment mechanism two for driving the backfill pipeline one (1) to retract to adjust the distance between the spray nozzle one (3) and the backfill pipeline two (2) and / or driving the backfill pipeline two (2) to retract to adjust the distance between the spray nozzle two (4) and the backfill pipeline one (1).

9. The active backfilling device for submarine cable laying according to claim 8, characterized in that, The telescopic pipeline includes two pipelines connected by a dynamic seal, and the second adjustment mechanism drives one of the pipelines to move axially along the other pipeline to perform telescoping.

10. An active backfilling method for submarine cable laying, characterized in that, An active backfilling device for submarine cable laying as described in any one of claims 1-9 is used, and the method includes the following steps: S1. Lower the lower ends of the second backfilling pipelines (2) in the two backfilling modules into the trench and position them on both sides of the cable (100). The first jet nozzle (3) is inclined downward in the direction of the trench above the seabed (200) towards the surface of the seabed (200), and the second jet nozzle (4) is inclined upward at the bottom of the trench towards the inner sidewall of the trench; S2. The jets ejected from the first jet nozzle (3) and the second jet nozzle (4) form an opposing jet, breaking the soil between the inner sidewall of the trench and the surface of the seabed (200), making it loose and collapsing into the trench for backfilling to bury the cable (100).

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