A shallow water flushing burying construction method and shallow water flushing burying system

Abstract

The application relates to a shallow water burying method and a shallow water burying system, and the method is applied to post-burying of laid submarine cables in extremely soft seabed and strong current environment, and comprises the following steps: hoisting a burying skid to the seabed along a submarine cable route where the laid submarine cable is located, so that a guide groove arranged at the bottom of the burying skid is astride on the laid submarine cable; supplying water to a high-pressure water flow mechanism at the bottom of the burying skid through a water pump barge via a water supply hose according to a working water supply flow, so as to execute fluidization on soft mud at the seabed below the burying skid to form a fluidized layer, and the burying skid is supported by suspension on the fluidized layer based on a skid base; starting a winch and applying a traction force to the burying skid along the submarine cable route via a traction steel wire rope, so that the burying skid slides along the submarine cable route, the laid submarine cable is sunk to a preset burying depth position corresponding to the bottom of the guide groove via the fluidized layer and is covered. The application has the advantages that the equipment is not sunken, not deviated, no underwater power is needed, no diver is needed, and accurate burying of the submarine cable can be completed under the working condition of extremely soft seabed and strong current.

Description

Technical Field

[0001] This application relates to the field of submarine cable burial construction technology, and in particular to a shallow water burial construction method and system. Background Technology

[0002] In submarine cable laying operations, existing submarine cables often need to be further buried into the seabed to prevent them from being snagged by fishing gear, anchored, or eroded by the seabed. Submarine cable burial operations require the submarine cables to be stably buried into the seabed at a predetermined depth along the original laying route, while taking into account the safety of underwater workers, the cross-current resistance of equipment, and adaptability to seabed conditions.

[0003] Existing submarine cable burial operations are generally carried out by two types of equipment: heavy-duty underwater trenching machines propelled by tracks or chain anchors, and lightweight, suspended burial equipment relying on underwater propulsion. The former suffers from slippage and instability on extremely soft seabeds with bearing capacities as low as 5 kPa, while the latter, in strong crosscurrents with current speeds reaching 2.0 m / s, is prone to drifting off the cable route due to its large surface area facing the current and lack of a route locking mechanism. This necessitates divers providing real-time underwater positioning and guidance, but the divers' working window in shallow water is short and the risks are high, further exacerbated by close proximity to already laid cables. The fundamental challenge faced by both types of equipment is that, in shallow water conditions with extremely soft seabeds and strong crosscurrents, it is impossible to simultaneously ensure that the equipment itself does not sink, drift, or rely on underwater propulsion, while also accurately burying the cable along its original route to the predetermined depth, all without the need for divers. Existing solutions cannot simultaneously meet these coupled constraints. Therefore, there has been a long-standing desire in the field to propose a diver-free shallow water flushing and burial method suitable for extremely soft seabeds and strong current environments. Summary of the Invention

[0004] In order to prevent the equipment from sinking, drifting, or relying on underwater power in shallow water conditions, and to ensure that the submarine cable is accurately buried to the predetermined depth along the original route, without relying on divers throughout the process, this application provides a shallow water flushing and burial construction method and a corresponding shallow water flushing and burial system.

[0005] Firstly, this application provides a shallow water flushing and burial construction method, which adopts the following technical solution: A shallow-water flushing and burial construction method, applied to the post-burial of already laid submarine cables, includes the following steps: S1. The burial sled is lowered to the seabed along the route of the laid submarine cable, so that the guide groove at the bottom of the burial sled straddles the laid submarine cable. The bottom of the burial sled is also equipped with a skid base. S2. Water is supplied to the high-pressure water fluidization mechanism at the bottom of the burial sled via a water pump barge and a water supply hose to fluidize the soft mud on the seabed below the burial sled. The fluidization forms a fluidized layer, and the burial sled obtains suspension support on the fluidized layer based on the skid base. S3. Start the winch and apply traction force to the burial sled along the coastal cable route via the traction wire rope, so that the burial sled slides along the coastal cable route. After the burial sled has slid through, the laid submarine cable sinks through the fluidized layer to the corresponding preset burial depth position at the bottom of the guide trough and is covered.

[0006] By adopting the above technical solution, the underwater functional responsibilities of the equipment are divided into three sequential and coordinated stages: fluidization, suspension, and traction. The pump barge provides high-pressure water-driven fluidization as the sole power source on the surface, eliminating the need for an underwater propulsion device on the burial skid itself. The wide contact surface of the skid base provides anti-sinking support on the suspension layer formed by fluidization, preventing the burial skid from sinking on the soft seabed. The guide channel locks the submarine cable at the bottom, forming a geometric constraint against crosscurrents, preventing the burial skid from sliding off the route in strong crosscurrents. The shore-based or shallow-water barge winch provides a single external traction source via steel cables, completely transferring the propulsion responsibility of the burial skid from underwater to the surface. The coordination of these four actions ensures that the entire construction process does not rely on any underwater power source or diver intervention. After passing through the fluidization layer, the submarine cable passively sinks to the corresponding height at the bottom of the guide channel, thus meeting the preset burial depth, forming a complete diver-free shallow-water burial technology path.

[0007] Optionally, S2 and S3 are coordinated to be divided into a pre-fluidization stage, a fluidization-traction synchronization stage, a constant velocity laying stage, and a final section fluidization retention stage within each construction segment of the submarine cable route. The construction segment is a continuous construction section on the submarine cable route. In the pre-fluidization stage, only the water pump barge is activated to supply water to form a fluidized layer. In the fluidization-traction synchronization stage, the water pump barge and the winch are activated in tandem. In the constant velocity laying stage, the burial skid slides at a constant speed to continuously sink the laid submarine cable to the preset burial depth. In the final section fluidization retention stage, the winch stops applying traction force, but the water pump barge continues to supply water. Each stage is switched sequentially according to preset switching conditions.

[0008] By adopting the above technical solution, a single construction section is divided into four sequential stages with clear switching conditions: pre-fluidization, fluidization-traction synchronization, constant speed burial, and final section fluidization retention. This decouples and coordinates fluidization and traction actions in the time dimension, avoiding situations where traction begins before sufficient fluidization, leading to sinking of the burial skid or failure of the submarine cable to sink to the preset burial depth when traction is stopped.

[0009] Optionally, during the execution of S2 and S3, multi-variable closed-loop construction control is performed on the water pump pressure of the water pump barge and the traction speed applied by the winch to the burial skid. The multi-variable closed-loop construction control uses the tension of the traction wire rope, the skid body posture of the burial skid, and the water supply flow of the water pump barge as feedback quantities, and performs linkage adjustment on the water pump pressure and traction speed according to the preset response rules.

[0010] By adopting the above technical solution, the pump pressure and traction speed are linked and adjusted by three feedback quantities distributed in different physical domains on the water surface and underwater: tension, attitude, and flow rate. This enables the fluidization-resistance-tension coupling system to maintain a steady state during construction under dynamic mud conditions and flow velocities.

[0011] Optionally, the winches include a front winch and a rear winch arranged opposite each other along the submarine cable route. The traction force is formed by the tension difference relationship between the front winch and the rear winch. During the execution of S3, in response to the lateral deviation of the skid attitude exceeding the preset tolerance zone detected by the multivariable closed-loop construction control, the tension difference relationship between the front winch and the rear winch is adjusted so that the heading of the burial skid returns to the preset tolerance zone of the submarine cable route.

[0012] By adopting the above technical solution, a controllable lateral correction component is formed by the tension difference between the front and rear winches, so that the sideslip tendency of the skid buried by the strong crossflow is compensated in real time, and the heading control is transferred from relying on underwater propulsion or manual positioning by divers to tension management of the surface winch.

[0013] Optionally, during the execution of S3, in response to an abnormal signal detected by the multivariate closed-loop construction control, an emergency rollback and re-fluidization restart operation is performed. The emergency rollback and re-fluidization restart operation includes, in sequence: using a winch to perform a reverse rollback along the coastal cable route of the burial sled, wherein the reverse rollback distance ensures that the guide trough and the laid submarine cable always maintain a straddle relationship; performing re-fluidization on the seabed mud at the current location of the burial sled; and restoring the application of forward traction force. In addition, if the abnormal signal still exists after the number of consecutive executions of the emergency rollback and re-fluidization restart operation reaches the preset number of retries, the current construction is suspended.

[0014] By adopting the above technical solution, a limited cycle self-rescue mechanism of reverse backflow, refluidization and restart is provided in abnormal working conditions such as jamming or abnormal flow. Moreover, the backflow distance is constrained by the straddling relationship between the guide channel and the submarine cable, so that the emergency action does not disengage from the straddling.

[0015] Optionally, before S1, a route pre-scan is performed along the submarine cable route, and the route is divided into multiple continuous construction sections according to the scan results of the route pre-scan, and a table of initial values ​​of construction parameters corresponding to each construction section is generated; the execution of S2 and S3 in each construction section also includes a trial push of the anti-impact sled, the trial push is carried out at a preset trial push speed that is less than the corresponding initial value in the table of initial values ​​of construction parameters, the parameters of the corresponding initial values ​​in the table of initial values ​​of construction parameters are corrected according to the tension change of the traction steel wire rope during the trial push, and the remaining construction of the construction section is completed with the corrected parameters.

[0016] By adopting the above technical solution, the route scan before construction provides segment-differentiated initial parameter values ​​for closed-loop control, and then the tension feedback of low-speed trial push is used to make on-site correction of the initial values, so that the construction parameters can adapt to the differences in mud quality and flow velocity between different segments of the same route.

[0017] Optionally, S1 includes sub-steps S11-S13.

[0018] S11. Using the pre-stored coordinate information of the submarine cable route, the sling is hoisted to the sea surface above the corresponding position of the submarine cable route via slings to complete the rough alignment.

[0019] S12. Control the sling to sink to the seabed and bury the skid. Determine the contact between the guide groove and the laid submarine cable based on the tension change of the sling, and complete the slow sinking and alignment.

[0020] S13. Water is supplied to the high-pressure fluidization mechanism by a water pump barge to test the water supply flow rate. Based on the position response of the burial skid relative to the submarine cable route, it is determined that the laid submarine cable is completely inside the guide groove, and the fine alignment is completed.

[0021] By adopting the above technical solution, the straddle alignment is broken down into three stages: coarse alignment, slow sinking alignment, and fine alignment, based on three criteria: coordinates, tension, and flow rate. The existing wire rope tension sensor and main water pump capacity are reused as alignment criteria, and straddle alignment in murky and shallow water areas can be completed without the need to add underwater visual or acoustic positioning mechanisms.

[0022] Optionally, S3 also includes a retrieval operation performed after the burial sled reaches the preset end position of the submarine cable route. The retrieval operation includes, in sequence: stopping the traction force of the winch and maintaining the water pump barge to continuously supply water so that the laid submarine cable is fully sunk to the preset burial depth; stopping the water supply of the water pump barge to allow the fluidized layer to re-solidify; applying reverse traction force through the winch to make the burial sled reverse back along the submarine cable route until the guide groove is disengaged from the straddling relationship with the laid submarine cable; and retrieving the burial sled.

[0023] By adopting the above technical solution, a specialized recovery sequence of final settlement, fluidized layer reconsolidation and reverse loosening is provided in the straddle-type working condition of the laid submarine cable, so that the burial skid can be withdrawn as a whole without cutting the submarine cable.

[0024] Optionally, the width of the guide groove is greater than the outer diameter of the laid submarine cable, and the difference between the width of the guide groove and the outer diameter of the laid submarine cable is less than the preset limit gap threshold.

[0025] By adopting the above technical solution, the lateral restraint formed by the guide groove on the laid submarine cable is directly supported by the geometric relationship between the groove width and the outer diameter of the submarine cable, and the restraint function no longer depends solely on the structural description.

[0026] Secondly, the shallow water flushing and burial system provided in this application adopts the following technical solution: A shallow water flushing and burial system, comprising: The burial skid has a guide groove at the bottom for laterally limiting the laid submarine cable when the burial skid straddles the laid submarine cable, a skid base on both sides of the guide groove, and a high-pressure water fluidization mechanism.

[0027] The water pump barge has its water pump outlet connected to the water supply end of the high-pressure water fluidization mechanism via a water supply hose. The water pump barge is configured to supply high-pressure water to the high-pressure water fluidization mechanism to fluidize the seabed mud under the burial skid to form a fluidized layer. The burial skid is suspended and supported on the fluidized layer based on the skid base.

[0028] The winch is connected to the burial skid via a traction steel wire rope. The winch is configured to apply traction to the burial skid along the route of the laid submarine cable, causing the burial skid to slide along the route of the submarine cable. After the laid submarine cable slides through the burial skid, it sinks through the fluidized layer to the corresponding preset burial depth position at the bottom of the guide trough.

[0029] The sensor is configured to monitor the operating parameters of the shallow water flushing system to provide feedback.

[0030] The controller communicates with the pump barge, winch, and sensors. The controller is configured to adjust the pump pressure of the pump barge and the traction speed applied by the winch to the sledge based on feedback.

[0031] By adopting the above technical solution, the underwater working body of the submarine cable burial system is decoupled from the surface power source and control center. The burial skid only undertakes the functions of fluidization, suspension and limiting, while the water pump barge and winch provide centralized power on the water surface. The controller manages the underwater operation status on the water surface through a closed loop of sensors. This allows the entire system to meet the compact configuration of no underwater propulsion, no divers, and a single underwater working body. It can still complete the precise burial of the laid submarine cable in shallow water conditions with soft seabed and strong cross currents.

[0032] Optionally, the winches include a front winch and a rear winch arranged opposite each other along the coastal cable route; the sensors of the shallow water flushing system include a tension sensor, an attitude sensor, and a flow sensor. The tension sensor is installed at least one end of the traction wire rope to monitor the tension of the traction wire rope, the attitude sensor is installed on the flushing skid to monitor the skid's attitude, and the flow sensor is installed at at least one end of the water supply hose to monitor the water flow rate supplied by the pump barge to the high-pressure fluidization mechanism; the tension of the traction wire rope, the skid's attitude, and the water flow rate supplied by the pump barge serve as feedback quantities; the controller is further configured to perform linkage adjustment of the pump pressure and traction speed according to the feedback quantities and preset response rules.

[0033] By adopting the above technical solution, the double winch structure, the arrangement of three sets of sensors and the closed-loop logic of the controller on the system side are mapped as a corresponding set, so that the preset control strategy of the whole system can obtain clear feedback, adjustment and correlation structure support.

[0034] In summary, this application includes at least one of the following beneficial technical effects: 1. In shallow water conditions where soft seabed and strong cross currents overlap, the coordinated division of labor between the skid base, guide channel, high-pressure water fluidization mechanism and surface winch traction allows the burial operation to complete the re-burial of the laid submarine cable along the original route to the preset burial depth without relying on underwater propulsion and divers.

[0035] 2. Through the layered superposition of control strategies such as four-stage timing coordination, multi-variable closed-loop construction control, dual winch differential crossflow compensation, emergency backoff and refluidization restart, route pre-scanning and segmented trial push parameter correction, three-stage straddle alignment, and final settlement and reverse loosening recovery, the construction process is able to adapt to dynamic mud quality, dynamic flow velocity, jamming anomalies, and the bending direction of the laid submarine cable.

[0036] 3. By limiting the lateral positioning of the cable by the guide groove and the outer diameter of the laid submarine cable through geometric relationship, the guide groove directly supports the cable by structural dimensions, thus fundamentally avoiding the risk of the cable jumping out of the groove under strong cross current. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the general layout of the shallow water flushing and burial system disclosed in an embodiment of this application; Figure 2 for Figure 1 Cross-sectional schematic diagram of the bottom structure of the central impact skid; Figure 3 This is a schematic diagram of the overall process of the shallow water flushing and burial construction method disclosed in the embodiments of this application; Figure 4 This is a block diagram of multivariable closed-loop construction control in a shallow water flushing and burial system disclosed in an embodiment of this application; Figure 5 This is a schematic diagram of the overall process for handling and recovering abnormalities in the S3 section of the shallow water flushing and burial construction method disclosed in this application.

[0038] Explanation of reference numerals in the attached figures: 100: Flushing skid; 110: Guide groove; 121: Left skid base; 122: Right skid base; 130: High-pressure water fluidization mechanism; 131: Fluid nozzle; 140: Front traction interface; 150: Rear traction interface; 200: Water pump barge; 210: Water pump; 220: Water supply hose; 310: Front winch; 320: Rear winch; 330: Front traction section; 340: Rear traction section; 400: Controller; 510: Tension sensor; 520: Attitude sensor; 530: Flow sensor; 700: Layed submarine cable; 800: Fluidization layer; 900: Sea surface. Detailed Implementation

[0039] This application discloses a shallow water flushing and burial construction method and system. The method divides the underwater burial operation into three coordinated stages: fluidization, suspension, and traction. A pump barge and winch provide centralized power on the water surface, while a controller manages the underwater operation status via a closed-loop sensor system. Only a single underwater working body, the flushing skid, is used, enabling the entire construction process to complete the re-burial of the pre-laid submarine cable along its original route to a predetermined depth without relying on any underwater propulsion devices or divers.

[0040] The following combination Figures 1 to 5 The shallow water flushing and burial construction method and shallow water flushing and burial system provided in the embodiments of this application are described in detail.

[0041] To ensure that the construction parameters can adapt to the differences in mud quality and flow velocity between different sections of the submarine cable route, in some embodiments, a route pre-scan is performed along the submarine cable route before S1.

[0042] The pre-scanning of the route includes three categories of objects: the distribution and thickness of seabed mud, the distribution of ocean current velocity in the waters corresponding to the submarine cable route, and the route curvature. The distribution and thickness of seabed mud can be obtained by scanning with a shallow seismic profiler, the distribution of ocean current velocity can be obtained by measuring with an acoustic Doppler current meter deployed along the route, and the route curvature is calculated from the sequence of route coordinate points recorded during the cable laying.

[0043] Based on the scanning results obtained from the route pre-scan, the submarine cable route is divided into multiple continuous construction segments. A table of initial construction parameters for each segment is generated, based on the seabed mud distribution thickness, ocean current velocity distribution, and route curvature. This table includes the initial water pump pressure of the pump barge 200 and the initial traction speed of the shovel 100 for each segment.

[0044] As an example, a 1000m submarine cable route is divided into 5-10 construction sections based on significant differences in the thickness of the seabed mud. For sections with thicker seabed mud, the initial pump pressure is increased to ensure sufficient fluidization layer 800, and the initial traction speed is decreased to prevent the burial skid 100 from sinking into the insufficiently fluidized mud. For sections with thinner seabed mud and lower current velocity, the initial pump pressure and traction speed are set to lower and higher values ​​respectively. This segment-differentiated initial parameter table provides the foundation for subsequent closed-loop control, allowing the construction process to adapt to changes in mud quality and flow velocity throughout the route without using the same set of constant parameters.

[0045] S1, the burial sled 100 is lowered to the seabed along the route of the laid submarine cable 700, so that the guide groove 110 at the bottom of the burial sled 100 straddles the laid submarine cable 700. The guide groove 110 generally refers to any inverted concave, gate-shaped or fence-shaped structure that can provide physical restraint on both sides of the submarine cable.

[0046] Reference Figure 2 As shown, in addition to the guide groove 110, the bottom of the burial skid 100 is also provided with a left skid base 121 and a right skid base 122, a high-pressure water fluidization mechanism 130, and a front traction interface 140 and a rear traction interface 150 located at the front and rear ends of the burial skid 100.

[0047] The guide groove 110 is a longitudinal groove extending along the length of the burial skid 100, with the groove opening facing downwards and its cross-sectional dimensions precisely enclosing the laid submarine cable 700.

[0048] The left skid base 121 and the right skid base 122 are located on both sides of the guide groove 110, and are the main load-bearing contact surfaces of the burial skid 100 on the seabed mud.

[0049] The high-pressure water fluidization mechanism 130 is integrated into the bottom of the flushing skid 100 and sprays high-pressure water downwards. It is the actuator in S2 that performs the fluidization of seabed mud.

[0050] The front traction interface 140 and the rear traction interface 150 are located at the front and rear ends of the burial skid 100, respectively, and are used to connect the corresponding sections of the traction wire rope.

[0051] In some embodiments, the width of the guide groove 110 is greater than the outer diameter of the laid submarine cable 700, and the difference between the width of the guide groove 110 and the outer diameter of the laid submarine cable 700 is less than a preset limiting gap threshold. For example, when the outer diameter of the laid submarine cable 700 is 200 mm, the width of the guide groove 110 can be 220 mm. The difference between the groove width and the outer diameter of the submarine cable is constrained by the preset limiting gap threshold, ensuring that the guide groove 110 allows the laid submarine cable 700 to pass smoothly through the groove without causing it to laterally detach from the groove under strong crosscurrent. That is, the lateral limiting function of the guide groove 110 for the laid submarine cable 700 is directly supported by the geometric relationship between the groove width and the outer diameter of the submarine cable.

[0052] In S1, the process of lowering the burial sled 100 along the coastal cable route to the seabed is carried out by a gantry crane or similar auxiliary lifting equipment. After being lowered to the seabed, the weight of the sled 100 is borne by the left skid base 121 and the right skid base 122. As an example, the projected area of ​​the bottom surface of the left skid base 121 and the right skid base 122 on one side can be taken as being on the order of 3m × 1m, so that the weight of the sled is distributed over a large supporting contact surface, thereby maintaining stable load-bearing without sinking on an extremely soft seabed of 5kPa.

[0053] S1 simultaneously establishes two geometric foundations for the subsequent execution of S2 and S3: First, the guide trough 110 has straddled the laid submarine cable 700, providing a geometric guidance channel for the submarine cable 700 to sink through the fluidized layer 800 to the preset burial depth position at the bottom of the guide trough 110 in S3; Second, the left skid base 121 and the right skid base 122 have contacted the seabed, providing a supporting foundation for the suspension support of the buried skid 100 after the fluidized layer 800 is formed in S2.

[0054] Reference Figure 3 As shown, specifically, S1 includes sub-steps S11-S13.

[0055] S11. Using pre-stored coordinate information of the submarine cable route, the sled 100 is hoisted to the sea surface 900 meters above the corresponding position of the submarine cable route via slings, completing the coarse alignment. The pre-stored coordinate information can be derived from route mapping data or GPS coordinate point sequences recorded during the laying phase of the submarine cable 700. The purpose of coarse alignment is to ensure that the sled 100 is approximately directly above the submarine cable 700 in the horizontal projection, providing an initial pose for subsequent slow sinking and fine alignment.

[0056] S12, control the sling to descend at a constant speed to bury the skid 100 to the seabed, continuously monitoring the sling tension during descent. When the sudden change in sling tension exceeds a preset threshold (e.g., 5%-10% of the baseline tension), determine that the guide groove 110 has contacted the laid submarine cable 700, completing the slow descent alignment. The physical meaning of the sudden change in sling tension when the guide groove 110 contacts the laid submarine cable 700 is that the submarine cable 700 begins to share some of the skid weight through the bottom of the guide groove 110. The skid weight, originally entirely borne by the sling, is now shared by the sling and the submarine cable 700, resulting in a corresponding decrease in sling tension.

[0057] S13, water is supplied to the high-pressure fluidization mechanism 130 at a test flow rate via the water pump barge 200. Based on the positional response of the burial skid 100 relative to the submarine cable route, it is determined that the laid submarine cable 700 is completely inside the guide trough 110, completing precise alignment. The test flow rate is lower than a preset percentage of the working flow rate, for example, 30%-50% of the working flow rate. The criterion is as follows: if the laid submarine cable 700 is not completely inside the guide trough 110, the water flow from the high-pressure fluidization mechanism 130 forms a lateral component at the skid bottom, causing slight lateral movement of the burial skid 100; if the submarine cable 700 is completely inside the guide trough 110, the water flow is constrained by the geometric relationship between the submarine cable 700 and the inner wall of the guide trough 110, and the burial skid 100 remains stable.

[0058] By using coordinates, tension, and flow rate as criteria, the straddle alignment is broken down into three stages: coarse alignment, slow sinking alignment, and fine alignment. Existing wire rope tension sensing and main water pump capacity are reused as alignment criteria to avoid the engineering difficulties of alignment in murky and shallow water areas due to the failure of underwater visual and acoustic positioning.

[0059] S2, water is supplied from the water pump barge 200 to the high-pressure water fluidization mechanism 130 at the bottom of the burial skid 100 via the water supply hose 220 at the working water supply flow rate, to fluidize the seabed mud below the burial skid 100. Fluidization forms a fluidization layer 800, and the burial skid 100 is suspended and supported on the fluidization layer 800 based on the left skid base 121 and the right skid base 122.

[0060] Continue to refer to Figure 2 As shown, the high-pressure water fluidization mechanism 130 specifically includes multiple rows of nozzles 131 evenly arranged along both sides and the leading edge of the guide channel 110. Each nozzle 131 sprays a high-pressure water jet downwards and slightly backwards, causing the seabed mud to mix with the high-pressure water under the hydraulic disturbance of the nozzles 131, forming a high-density water-mud mixture suspension. The water pump barge 200 is moored at the sea surface 900 of the water area where the sled 100 is located. The outlet of the water pump 210 installed on the water pump barge 200 is connected to the water supply end of the high-pressure water fluidization mechanism 130 through a water supply hose 220, forming a single high-pressure water transport link from the water surface to the underwater environment.

[0061] As an example, the working water supply flow rate can be taken as 200-400 m³ / h, and the corresponding outlet pressure of the water pump 210 can be taken as 0.6-1.2 MPa. Under the high-pressure water drive at this level, the seabed soft mud about 0.3-0.5 m thick at the bottom of the burial sled 100 is fluidized to form a fluidized layer 800. After the formation of the fluidized layer 800, the original bearing capacity of the soft mud in the range of 5 kPa drops to an extremely low value in the fluidized state, so that the weight of the sled 100 is transferred from being directly borne by the original soft mud to being borne by the water-mud mixed suspension support in the fluidized layer 800.

[0062] The physical mechanism by which the wide contact surfaces of the left skid base 121 and the right skid base 122 obtain suspension support on the fluidized layer 800 is as follows: the water-mud mixture suspension in the fluidized layer 800 has a certain pressure bearing capacity, similar to dense mud; the wide contact surfaces of the skid bases 121 / 122 distribute the weight of the burial skid 100 to a larger suspension contact surface, making the pressure per unit area lower than the pressure bearing capacity of the fluidized layer 800, so that the burial skid 100 can maintain a stable suspension state on the fluidized layer 800 without sinking.

[0063] It should be noted that the water supply in this step is based on the working water supply flow rate, which differs from the trial water supply flow rate used in the S13 fine alignment stage. The working water supply flow rate is the nominal water supply flow rate used in the S2 fluidization stage and the S3 traction and burial stage, sufficient to maintain the continuous formation of the fluidized layer at 80°; the trial water supply flow rate is a lower value of its preset proportion, used only as a criterion for fine alignment. The flow rate threshold monitoring in the multivariate closed-loop construction control described below is only activated in the S2 fluidization stage and the S3 traction and burial stage; the trial water supply flow rate in the S13 fine alignment stage is not included in this monitoring scope.

[0064] Reference Figure 3 As shown, in some embodiments, S2 and S3 are coordinated to be divided into a pre-fluidization stage, a fluidization-traction synchronization stage, a constant velocity laying stage and a final section retention fluidization stage in each construction segment of the submarine cable route. The construction segment is a continuous construction section on the submarine cable route.

[0065] During the pre-fluidization stage, only the water pump barge 200 is started to supply water to form the fluidized bed 800, while the winches 310 / 320 have not yet been started. The switching condition for the pre-fluidization stage is that the water supply flow of the water pump barge 200 enters the preset steady-state range, for example, the fluctuation range of the water supply flow is less than ±5% of the working water supply flow.

[0066] During the fluidization-traction synchronization phase, the pump barge 200 and winches 310 / 320 start in tandem, and the winches 310 / 320 begin to apply traction force to the sled 100 via the traction wire rope. The switching condition for the fluidization-traction synchronization phase is that the tension of the traction wire rope enters the preset steady-state tension range.

[0067] During the constant speed burial stage, the burial sled 100 slides along the coastal cable route at a preset traction speed, and the laid submarine cable 700 continues to sink through the fluidized layer 800 to the preset burial depth position; the switching condition for the constant speed burial stage is that the burial sled 100 reaches the end position of the current construction section.

[0068] During the final stage of fluidization retention, winches 310 / 320 cease applying traction, but the water pump barge 200 continues to supply water to maintain the fluidization layer 800 for the preset retention time. The final stage of fluidization retention ends when the tension of the traction wire rope drops to the preset fall-off range.

[0069] By dividing a single construction section into four sequential stages with clear switching conditions—pre-fluidization, fluidization-traction synchronization, constant-speed burial, and final-stage fluidization retention—fluidization and traction actions are decoupled and coordinated in the time dimension. This avoids situations where traction is initiated before sufficient fluidization, causing the burial skid 100 to sink, or where water supply is immediately stopped when traction is stopped, resulting in the fluidization layer 800 rapidly solidifying while the laid submarine cable 700 has not fully sunk to the preset burial depth.

[0070] Reference Figure 4As shown, in some embodiments, during the execution of S2 and S3, multivariate closed-loop construction control is performed on the water pump pressure of the water pump barge 200 and the traction speed applied by the winch 310 / 320 to the burial skid 100. The multivariate closed-loop construction control uses the tension of the traction wire rope, the skid posture of the burial skid 100, and the water supply flow rate of the water pump barge 200 as feedback quantities, and performs linkage adjustment on the water pump pressure and traction speed according to preset response rules.

[0071] Tension sensor 510 is disposed at at least one end of the traction wire rope, attitude sensor 520 is disposed on the shovel 100, and flow sensor 530 is disposed at at least one end of the water supply hose 220. Controller 400 is disposed on the water surface, for example, on the water pump barge 200, and transmits feedback data to the aforementioned sensors via wired or wireless communication links. As an example, the control execution frequency of controller 400 is on the order of 10 Hz, and the sampling frequency of each sensor is on the order of 50-100 Hz.

[0072] The specific preset response rules include three types of conditional responses: tension exceeding the threshold increases pump pressure, attitude deviation reduces traction speed, and flow rate falling below the threshold triggers a blockage alarm.

[0073] In response to the tension of the traction wire rope exceeding the preset upper tension threshold, such as 80kN, the water pump pressure is increased in a direction positively correlated with the amount of tension exceeding the threshold. For example, when the actual tension exceeds the threshold by 10kN, the water pump pressure is increased by 0.05-0.1MPa accordingly.

[0074] If the pitch angle deviation of the burial skid 100 exceeds a preset pitch angle deviation threshold, such as ±3°, the traction speed is reduced in a direction negatively correlated with the pitch angle deviation. For example, when the pitch angle deviates by 5°, the traction speed is reduced by 20%-30% accordingly.

[0075] In response to the water supply flow rate of the water pump barge 200 being lower than a preset flow rate threshold, such as being lower than 70% of the working water supply flow rate, a blockage alarm is triggered on the nozzle 131 of the high-pressure water fluidization mechanism 130.

[0076] The fluidization-resistance-tension coupling system maintains a steady state during construction under dynamic mud conditions and flow velocities by driving the coordinated adjustment of pump pressure and traction speed through three feedback quantities distributed in different physical domains: tension, attitude, and flow rate. Specifically, the flow rate feedback is located in the surface section, between the pump barge 200 and the water supply hose 220; the tension feedback is located at the end of the wire rope; and the attitude feedback is located in the underwater section. Together, these three components form a complete surface and underwater coupling closed loop.

[0077] S3, start the winches 310 / 320 and apply traction force to the burial sled 100 along the coastal cable route via the traction wire rope, so that the burial sled 100 slides along the coastal cable route. After the burial sled 100 slides through, the laid submarine cable 700 sinks through the fluidization layer 800 to the preset burial depth position corresponding to the bottom of the guide trough 110 and is covered.

[0078] Winches 310 / 320 are deployed on shore-based or shallow-water auxiliary barges corresponding to the submarine cable route where the laid submarine cable 700 is located. The traction wire rope is laid along the submarine cable route via the water surface or shallow water section and is connected to the front traction interface 140 and the rear traction interface 150 of the burial skid 100, respectively. By raising and lowering the traction wire rope, winches 310 / 320 can apply a traction force to the burial skid 100 in the direction of the submarine cable route, causing the burial skid 100 to slide on the fluidized layer 800 formed by S2.

[0079] As an example, the speed at which the winch 310 / 320 raises and lowers the traction wire rope can be taken as 0.1-0.3 m / s, and the corresponding construction section length can be taken as 50-200 m. At this traction speed, the burial skid 100 slides along the coastal cable route at a constant speed, and the laid submarine cable 700, which was originally located on the seabed surface, is gradually guided by the guide trough 110 to sink below the soft mud on the seabed.

[0080] The physical mechanism by which the laid submarine cable 700 sinks to the preset burial depth via the fluidization layer 800 is as follows: At the instant the burial sled 100 passes, the seabed mud at the bottom of the guide channel 110 is fluidized into the fluidization layer 800. Under its own gravity, the laid submarine cable 700 sinks through the fluidization layer 800 and is geometrically guided by the inner wall of the guide channel 110 to the corresponding longitudinal height position at the bottom of the guide channel 110; this longitudinal height position is the preset burial depth. As an example, the preset burial depth can be a typical value of 1.5-3m below the seabed surface. After the burial sled 100 passes, the fluidization layer 800 is redeposited and solidified under gravity, covering the laid submarine cable 700, which has sunk to the preset burial depth, back beneath the seabed mud.

[0081] In S3, the propulsion of the entire burial skid 100 is entirely undertaken by the surface winches 310 / 320 and the support facilities on shore or in shallow water, without any underwater propulsion device. At the same time, the sinking of the laid submarine cable 700 is a passive sinking mechanism based on the weakening of the support of the fluidized layer 800, the self-weight of the submarine cable 700, and the guidance of the guide trough 110, without any underwater active burial device.

[0082] Reference Figure 1As shown, in some embodiments, winches 310 / 320 include a front winch 310 and a rear winch 320 arranged opposite each other along the submarine cable route. The front winch 310 is deployed at the forward distal end of the submarine cable route, i.e., in the direction the burial sled 100 is about to slide to; the rear winch 320 is deployed at the backward distal end of the submarine cable route, i.e., in the direction the burial sled 100 has already slid through. The traction wire rope includes a front traction section 330 connecting the front winch 310 and the front traction interface 140 of the burial sled 100, and a rear traction section 340 connecting the rear winch 320 and the rear traction interface 150 of the burial sled 100. The traction force on the burial sled 100 in S3 is formed by the differential relationship between the front tension applied by the front winch 310 through the front traction section 330 and the rear tension applied by the rear winch 320 through the rear traction section 340. When the difference is positive, the burial sled 100 slides forward.

[0083] During the execution of S3, in response to the lateral deviation of the sled attitude exceeding the preset tolerance zone detected by the multivariable closed-loop construction control, the tension difference relationship between the front winch 310 and the rear winch 320 is adjusted to bring the heading of the burial sled 100 back to the preset tolerance zone of the submarine cable route. As an example, the preset tolerance zone can be taken as the lateral deviation of the burial sled 100 relative to the submarine cable route on the order of ±0.5m; when the attitude sensor 520 detects that the lateral deviation exceeds this tolerance zone, the controller 400 forms a lateral correction component by adjusting the difference between the front tension and the rear tension, for example, by adjusting the front tension accordingly and the rear tension accordingly to pull the sled heading back.

[0084] The tension difference between the front winch 310 and the rear winch 320 forms a controllable lateral correction component, transferring heading control from reliance on underwater propulsion or manual positioning by divers to tension management of the surface winch.

[0085] Reference Figure 5 As shown, in some embodiments, during the execution of S3, in response to an abnormal signal detected by the multivariate closed-loop construction control, an emergency rollback and refluidization restart operation is performed. The specific forms of the abnormal signal include two typical scenarios: the first is that the tension of the traction wire rope exceeds a preset abnormal tension threshold, for example, on the order of 120 kN, indicating that the flushing skid 100 may encounter a hard obstacle or be stuck on the route; the second is that the water supply flow of the pump barge 200 is continuously lower than a preset lower flow threshold, for example, lower than 50% of the working water supply flow, and continues for more than a preset duration, for example, 5-10 seconds, indicating that the nozzle 131 of the high-pressure water fluidization mechanism 130 may be severely clogged.

[0086] The emergency rollback and refluidization restart operation includes three actions in sequence: reverse rollback, current position refluidization, and forward restart traction.

[0087] First, the burial skid 100 is reversed along the submarine cable route by winch 310 / 320. The reverse retraction distance is constrained by the straddling relationship between the guide groove 110 and the laid submarine cable 700. As an example, the upper limit of the reverse retraction distance can be taken as 50% of the longitudinal dimension of the guide groove 110 along the length of the skid, to ensure that the guide groove 110 does not completely detach from the laid submarine cable 700.

[0088] After the reverse retraction is completed, the seabed mud at the current location of the sled 100 is refluidized by increasing the water pump pressure to the preset refluidization pressure, such as 80%-90% of the maximum output pressure of the water pump 210, to enhance the fluidization of the mud at the current location and soften any possible jamming points.

[0089] The refluidization lasts for a preset duration, such as 30-60 seconds, after which the forward traction is restored, allowing the sled 100 to attempt forward sliding along the coastal cable route again.

[0090] In addition, if the abnormal signal persists after the number of consecutive executions of the emergency rollback and refluidization restart operations reaches the preset retry count, the current construction will be suspended and an alarm will be issued. The preset retry count can be on the order of 2-3 times. If the abnormality cannot be resolved after exceeding this number, it indicates that the seabed conditions in this section exceed the handling capacity of the 100-meter shovel, and construction must be stopped and manual intervention is required for diagnosis.

[0091] In some embodiments, the execution of S2 and S3 within each construction segment also includes a trial push of the burial sled 100. The trial push is performed at a preset trial push speed that is less than the corresponding initial value in the initial value table of construction parameters. For example, the preset trial push speed can be taken as 30%-50% of the initial value of the traction speed in the initial value table of construction parameters, so that the burial sled 100 slides along a preset trial push distance in the construction segment at a low speed. The preset trial push distance can be taken as the first 10%-20% of the length of the current construction segment.

[0092] Based on the tension changes of the traction wire rope during the trial push, the initial values ​​in the initial value table of construction parameters are corrected. Specifically: if the actual tension of the traction wire rope during the trial push is higher than the expected tension value in the initial value table of construction parameters, then the actual mud resistance of the current construction section is higher than the expected mud resistance corresponding to the scanning results. The water pump pressure is corrected upwards, for example, by 5%-15%, to enhance fluidization, and the traction speed is corrected downwards, for example, by 10%-20%, to reduce drag resistance. If the actual tension is lower than the expected value, then the actual mud resistance of the current construction section is lower than expected. The water pump pressure is corrected downwards, and the traction speed is corrected upwards to avoid excessive fluidization and wasting the capacity of the water pump 210. After the parameter correction is completed, the corrected water pump pressure and traction speed are used as the actual working parameters for the remaining distance of this construction section.

[0093] The initial values ​​of construction parameters obtained from route pre-scanning reflect macroscopic inferences based on macroscopic geophysical data such as mud thickness, flow velocity, and curvature. However, the actual mud resistance of a single section of the seabed is also affected by factors such as mud water content, particle size distribution, and micro-stratigraphic structure. These micro-differences are difficult to predict in advance through pre-scanning, while the actual tension feedback obtained from low-speed trial pushes can reflect the true mud resistance of this section, providing on-site data basis for the local correction of construction parameters.

[0094] Continue to refer to Figure 5 As shown, S3 also includes a retrieval operation performed after the burial skid 100 reaches the preset endpoint of the submarine cable route. The retrieval operation includes four actions in sequence: endpoint retention settlement, stopping water supply to reconsolidate the fluidized layer, reverse loosening, and skid retrieval.

[0095] First, stop the traction force applied by winches 310 / 320 to the burial skid 100, and maintain the continuous water supply from the pump barge 200 to keep the fluidized layer 800 in place for the preset retention settlement time, thus performing the final retention settlement. As an example, the preset retention settlement time can be on the order of 5-10 minutes. Within this time, the laid submarine cable 700 will fully sink to the preset burial depth position corresponding to the bottom of the guide trough 110 under its own gravity. This final retention settlement is located at the preset end position of the entire submarine cable route, distinct from the final section retention fluidization stage at the end of each construction section (S2 and S3).

[0096] After the preset settling period ends, the water supply from the pump barge 200 is stopped, allowing the fluidized layer 800 to re-solidify under gravity. As an example, the condition for determining the re-solidification of the fluidized layer 800 can be taken as 5-15 minutes after the water supply is stopped. At this time, the fluidized layer 800 returns from a water-mud mixed suspension state to a sedimentary and solidified state, and the laid submarine cable 700 is stably wrapped by the surrounding re-solidified soft mud at the preset burial depth.

[0097] Then, the winches 310 / 320 apply reverse traction to cause the burial skid 100 to reverse back along the coastal cable route until the guide groove 110 is no longer straddling the laid submarine cable 700. As an example, the reverse back-retraction distance can be slightly greater than the longitudinal dimension of the guide groove 110 along the length of the skid, which allows the guide groove 110 to be completely removed from directly above the laid submarine cable 700, thus releasing the straddling relationship.

[0098] Finally, the sled 100 is retrieved from the seabed to the surface of the water using a gantry crane or similar auxiliary lifting equipment.

[0099] By performing four sequential sub-actions—end point retention settlement, fluidized layer reconsolidation, reverse loosening, and skid recovery—the burial skid 100 can be withdrawn as a whole without cutting the laid submarine cable 700, thus avoiding pulling on the submarine cable 700 that has not yet been fully consolidated and covered during reverse retraction.

[0100] Reference Figure 1 As shown in the embodiments of this application, a shallow water flushing and burial system is also disclosed. This shallow water flushing and burial system corresponds to the above-mentioned shallow water flushing and burial construction method, and each hardware component of the system undertakes the corresponding responsibility in each step of the method.

[0101] The shallow water flushing and burial system includes a flushing skid 100, a pump barge 200, winches 310 / 320, sensors 510 / 520 / 530, and a controller 400.

[0102] The burial skid 100 is the only underwater working body in the system, responsible for the straddle alignment in S1 and the suspension support during fluidization in S2. The bottom of the burial skid 100 is provided with a guide groove 110 for laterally limiting the laid submarine cable 700 when the burial skid 100 straddles the laid submarine cable 700, a left skid base 121 and a right skid base 122 located on both sides of the guide groove 110, and a high-pressure water fluidization mechanism 130; the guide groove 110 provides lateral limiting, the left skid base 121 and the right skid base 122 provide anti-sinking suspension support contact surfaces, and the high-pressure water fluidization mechanism 130 provides the fluidization effect in S2.

[0103] The pump barge 200 is moored at sea surface 900 in the waters where the burial skid 100 is located, and undertakes the water supply responsibility in S2. The pump barge 200 integrates a water pump 210, and the water outlet of the water pump 210 is connected to the water supply end of the high-pressure water fluidization mechanism 130 through a water supply hose 220. The pump barge 200 is configured to supply high-pressure water to the high-pressure water fluidization mechanism 130 to fluidize the seabed mud below the burial skid 100 to form a fluidized layer 800, so that the burial skid 100 is suspended and supported on the fluidized layer 800 based on the left skid base 121 and the right skid base 122.

[0104] The winches 310 / 320 are connected to the burial skid 100 via traction steel wire ropes and undertake the traction function in S3. In some embodiments, the winches 310 / 320 include a front winch 310 and a rear winch 320 arranged opposite each other along the coastal cable route. The winches 310 / 320 are deployed on the shore base or shallow water auxiliary barge corresponding to the submarine cable route where the laid submarine cable 700 is located, and are configured to apply traction force to the burial skid 100 along the coastal cable route, causing the burial skid 100 to slide along the coastal cable route. After the laid submarine cable 700 slides through the burial skid 100, it sinks through the fluidization layer 800 to the preset burial depth position corresponding to the bottom of the guide trough 110.

[0105] Sensors 510 / 520 / 530 are configured to monitor operating parameters of the shallow water flushing system to provide feedback. In some embodiments, the sensors include a tension sensor 510, an attitude sensor 520, and a flow sensor 530. The tension sensor 510 is disposed at at least one end of the traction wire rope to monitor the tension of the traction wire rope; the attitude sensor 520 is disposed on the flushing skid 100 to monitor the skid attitude of the flushing skid 100; and the flow sensor 530 is disposed at at least one end of the water supply hose 220 to monitor the water flow rate supplied by the pump barge 200 to the high-pressure water fluidization mechanism 130. The tension of the traction wire rope, the skid attitude, and the water flow rate supplied by the pump barge 200 serve as feedback for the controller 400.

[0106] The controller 400 is communicatively connected to the pump barge 200, winches 310 / 320, and sensors 510 / 520 / 530, serving as the central control unit for multivariable closed-loop construction control. The controller 400 is configured to adjust the pump pressure of the pump barge 200 and the traction speed applied by the winches 310 / 320 to the sledge 100 based on feedback values. In some embodiments, the controller 400 is further configured to perform coordinated adjustment of the pump pressure and traction speed based on feedback values ​​and preset response rules. The controller 400 is typically located on the water surface, such as on the pump barge 200, and transmits feedback data to the sensors via wired or wireless communication links.

[0107] By decoupling the underwater working body of the submarine cable burial system from the surface power source and control center, the burial skid 100 only undertakes the functions of fluidization, suspension and limiting, while the water pump barge 200 and winches 310 / 320 provide centralized power on the surface, and the controller 400 manages the underwater operation status through a closed loop of sensors on the surface, so that the entire system can meet the compact configuration of no underwater propulsion, no divers, and a single underwater working body.

[0108] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A shallow-water flushing and burial construction method, applied to the post-burial of already laid submarine cables, characterized in that, Includes the following steps: S1. The burial sled is lowered to the seabed along the route of the laid submarine cable, so that the guide groove at the bottom of the burial sled straddles the laid submarine cable. The bottom of the burial sled is also provided with a skid base. S2. Water is supplied to the high-pressure water fluidization mechanism at the bottom of the burial sled via a water pump barge and a water supply hose to fluidize the seabed mud under the burial sled. The fluidization forms a fluidized layer, and the burial sled obtains suspension support on the fluidized layer based on the skid base. S3. Start the winch and apply traction force to the burial sled along the submarine cable route using the traction steel wire rope, so that the burial sled slides along the submarine cable route. After the burial sled has slid through, the laid submarine cable sinks through the fluidized layer to the preset burial depth position corresponding to the bottom of the guide groove and is covered.

2. The shallow water flushing and burial construction method according to claim 1, characterized in that, S2 and S3 are coordinated to divide each construction section of the submarine cable route into a pre-fluidization stage, a fluidization-traction synchronization stage, a constant velocity laying stage, and a final section fluidization retention stage, which are sequentially included. The construction section is a continuous construction interval on the submarine cable route. In the pre-fluidization stage, only the water pump barge is activated to supply water to form the fluidization layer. In the fluidization-traction synchronization stage, the water pump barge and the winch are activated in tandem. In the constant velocity laying stage, the burial skid slides at a constant speed to continuously sink the laid submarine cable to the preset burial depth. In the final section fluidization retention stage, the winch stops applying the traction force, but the water pump barge continues to supply water. Each stage is switched sequentially according to preset switching conditions.

3. The shallow water flushing and burial construction method according to claim 1, characterized in that, During the execution of S2 and S3, multi-variable closed-loop construction control is performed on the water pump pressure of the water pump barge and the traction speed applied by the winch to the burial skid. The multi-variable closed-loop construction control uses the tension of the traction wire rope, the skid body posture of the burial skid, and the water supply flow of the water pump barge as feedback quantities, and performs linkage adjustment on the water pump pressure and the traction speed according to the preset response rules.

4. The shallow water flushing and burial construction method according to claim 3, characterized in that, The winches include a front winch and a rear winch arranged opposite each other along the submarine cable route. The traction force is formed by the tension difference relationship between the front winch and the rear winch. During the execution of S3, in response to the lateral deviation of the skid attitude exceeding the preset tolerance zone detected by the multivariable closed-loop construction control, the tension difference relationship between the front winch and the rear winch is adjusted so that the heading of the burial skid returns to the preset tolerance zone of the submarine cable route.

5. The shallow water flushing and burial construction method according to claim 3, characterized in that, During the execution of S3, in response to the abnormal signal detected by the multivariate closed-loop construction control, an emergency rollback and re-fluidization restart operation is performed. The emergency rollback and re-fluidization restart operation includes, in sequence: using the winch to cause the burial sled to roll back in the reverse direction along the submarine cable route, wherein the distance of the reverse rollback is such that the guide trough and the laid submarine cable always maintain a straddle relationship; re-fluidizing the seabed mud at the current location of the burial sled; and restoring the forward application of the traction force. In addition, if the abnormal signal still exists after the number of consecutive executions of the emergency rollback and re-fluidization restart operation reaches a preset number of retries, the current construction is suspended.

6. The shallow water flushing and burial construction method according to claim 1, characterized in that, Before step S1, a route pre-scan is performed along the submarine cable route, and the submarine cable route is divided into multiple continuous construction segments according to the scanning results of the route pre-scan, and a table of initial values ​​of construction parameters corresponding to each construction segment is generated. Steps S2 and S3 in each construction segment also include performing a trial push on the burial skid. The trial push is performed at a preset trial push speed that is lower than the corresponding initial value in the table of initial values ​​of construction parameters. The parameters of the corresponding initial values ​​in the table of initial values ​​of construction parameters are corrected according to the tension change of the traction steel wire rope during the trial push, and the remaining construction of the construction segment is completed with the corrected parameters.

7. The shallow water flushing and burial construction method according to claim 1, characterized in that, S1 includes the following sub-steps: S11. According to the pre-stored coordinate information of the submarine cable route, the sling is hoisted to the sea surface above the corresponding position of the submarine cable route using slings to complete the rough alignment; S12. Control the sling to sink the burial skid to the seabed, and determine the contact of the guide groove with the laid submarine cable according to the tension change of the sling, so as to complete the slow sinking and alignment; S13. Water is supplied to the high-pressure fluidization mechanism by the water pump barge at a test flow rate. Based on the position response of the burying skid relative to the submarine cable route, it is determined that the laid submarine cable is completely inside the guide groove, thus completing the precise alignment.

8. The shallow water flushing and burial construction method according to claim 1, characterized in that, S3 further includes a retrieval operation performed after the burial sled reaches the preset end position of the submarine cable route. The retrieval operation includes, in sequence: stopping the traction force of the winch and maintaining the water pump barge to continuously supply water so that the laid submarine cable is fully submerged to the preset burial depth; stopping the water supply of the water pump barge to resolidify the fluidized layer; applying the traction force in the opposite direction through the winch to cause the burial sled to reverse along the submarine cable route until it disengages from the straddling relationship with the laid submarine cable in the guide groove; and retrieving the burial sled.

9. A shallow water flushing and burial system, characterized in that, include: The burial skid has a guide groove at its bottom for laterally limiting the laid submarine cable when the burial skid straddles the laid submarine cable, a skid base located on both sides of the guide groove, and a high-pressure water fluidization mechanism. A water pump barge, the water pump outlet of which is connected to the water supply end of the high-pressure water fluidization mechanism via a water supply hose, the water pump barge being configured to supply high-pressure water to the high-pressure water fluidization mechanism to fluidize the seabed mud below the burial skid to form a fluidized layer, the burial skid being suspended and supported on the fluidized layer based on the skid base; A winch is connected to the burial sled via a traction steel wire rope. The winch is configured to apply traction to the burial sled along the submarine cable route where the laid submarine cable is located, causing the burial sled to slide along the submarine cable route. After the burial sled passes through the burial sled, the laid submarine cable sinks through the fluidized layer to the preset burial depth position corresponding to the bottom of the guide groove. Sensors are configured to monitor the operating parameters of the shallow water flushing system to provide feedback. A controller, communicatively connected to the pump barge, the winch, and the sensor, is configured to adjust the pump pressure of the pump barge and the traction speed applied by the winch to the shovel based on the feedback.

10. The shallow water flushing and burial system according to claim 9, characterized in that, The winches include a front winch and a rear winch arranged opposite each other along the submarine cable route. The sensors include a tension sensor, an attitude sensor, and a flow sensor. The tension sensor is disposed at at least one end of the traction wire rope to monitor the tension of the traction wire rope. The attitude sensor is disposed on the burial skid to monitor the skid's attitude. The flow sensor is disposed at at least one end of the water supply hose to monitor the water flow rate supplied by the water pump barge to the high-pressure water fluidization mechanism. The tension of the traction wire rope, the skid's attitude, and the water supply flow rate of the water pump barge serve as the feedback quantities. The controller is further configured to perform linkage adjustment of the water pump pressure and the traction speed according to the feedback amount and the preset response rules.

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