A multi-point support type submarine cable anchoring device and anchoring construction method

Abstract

This application mainly relates to the field of submarine cable anchoring devices, specifically a multi-point supported submarine cable anchoring device and anchoring construction method. The anchoring device includes a base and a cable support mounted on the base. The bottom of the base is provided with a side plate, and a rotating shaft is installed on the side plate. An angle adjustment structure is provided between the rotating shaft and the base. An anchor bolt assembly is installed at the outer end of each rotating shaft. The anchor bolt assembly includes multiple anchor bolts with expansion sleeves. The angle adjustment structure includes a locking nut and an adjusting nut. The rotating shaft hole is provided with a rotating groove. The adjusting nut is embedded in the rotating groove. The bottom surface of the rotating groove is provided with an indexing groove. The adjusting nut has a first end and a second end along the axial direction. The first end has an indexing tooth, which is inserted into the indexing groove along the axial direction to limit the angle of the rotating shaft. The second end has a sliding part, which slides with the rotating groove to allow the base to rotate freely. This anchoring device and anchoring construction method have the advantage of improving the stress on the anchor bolts.

Description

Technical Field

[0001] This invention relates to the field of submarine cable anchoring devices, and in particular to a multi-point supported submarine cable anchoring device and anchoring construction method. Background Technology

[0002] Submarine cables are subject to long-term marine environmental loads such as ocean currents, tides, and waves, making them prone to displacement and dragging. Stress is concentrated at landing sections and route inflection points, directly impacting the stability and operational safety of the cables after installation. Therefore, submarine cable anchoring devices are necessary to secure the cables at fixed points.

[0003] Submarine cables have high axial stiffness but low lateral stiffness. When a distributed force perpendicular to the axial direction acts on the cable's suspended section, the cable will bend significantly and transmit the huge lateral resultant force to the anchor points at both ends through the wind-catching effect, generating a huge horizontal drag force on the cable support of the anchoring device. In addition, near the landing section, submarine cables usually extend towards the end anchoring node at a certain angle. Under the action of pretension and wind, waves and currents, submarine cables will generate a huge vertical pull force on the submarine anchoring point. Therefore, the underwater anchoring device of submarine cables is mainly subjected to the resultant force of horizontal drag force and vertical pull force.

[0004] Existing submarine cable anchoring devices typically include a submarine base, a cable support frame, and multiple anchor piles. The cable support frame is installed on the submarine base, and the anchor piles connect the submarine base to the seabed. The anchor piles are generally driven into the seabed in a fixed vertical manner, which cannot flexibly adjust their attitude according to the undulating seabed topography and the actual direction of the resultant force of ocean currents. This causes the anchor piles or anchor rods to be subjected to extremely large lateral shear stress and bending moment for a long time, making the expansion sleeve, which plays a role in preventing pull-out, prone to failure or even fatigue fracture.

[0005] Therefore, there is an urgent need for an anchoring device and anchoring construction method that can anchor and support submarine cables according to the seabed topography and the actual direction of the resultant force of ocean currents. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a multi-point supported submarine cable anchoring device and anchoring construction method.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A multi-point supported submarine cable anchoring device includes a base and a cable support mounted on the base. One or more cable clamps are provided on the cable support. Side seats are provided on both sides of the bottom of the base along the cable length direction. Each side seat has a pivot hole extending along the cable length direction. A pivot is installed in the pivot hole. An angle adjustment structure is provided between the pivot and the base. An anchor bolt assembly is installed at the outer end of each pivot. The anchor bolt assembly includes multiple anchor bolts with expansion sleeves. The angle adjustment structure includes: An external thread section and an internal thread section are provided on the rotating shaft and separated on both sides of the rotating shaft hole; A locking nut connected to the internal thread section; An adjusting nut connected to the external thread section; The outer end of the rotating shaft hole is coaxially provided with a rotating groove, and the adjusting nut is embedded in the rotating groove. The bottom surface of the rotating groove is provided with an indexing groove. The adjusting nut has a first end and a second end along the axial direction. The first end has an indexing tooth, which is inserted into the indexing groove along the axial direction to limit the angle of the rotating shaft. The second end has a sliding part, which slides with the rotating groove to allow the base to rotate freely.

[0008] To optimize the above solution, the following technical measures were also adopted: As a preferred embodiment, the anchor bolt assembly includes a seat fixedly disposed at the outer end of the rotating shaft, the seat having at least two anchor bolts disposed radially on both sides of the rotating shaft, the seat having a vertical fixing sleeve, the outer peripheral wall of the anchor bolt having a helical blade, the helical blade being screwed into the fixing sleeve, and the upper end of the anchor bolt having a rotating cap.

[0009] As a preferred embodiment, the anchor bolt has a hollow inner cavity, within which a locking structure is provided. The locking structure includes a central threaded sleeve disposed within a rotating cap, and a movable rod is threadedly connected within the central threaded sleeve. The movable rod is vertically inserted into the hollow inner cavity. The upper end of the movable rod is provided with an external hexagonal block, and the lower end is provided with a conical extrusion head. Expansion sleeves are provided on both radial sides of the lower end of the hollow inner cavity, and wedges are provided on the inner side of the expansion sleeves. The extrusion head and the wedges abut against each other vertically. By spiraling the movable rod downwards, the extrusion head can be pushed downwards to extrude the wedges, thereby pushing the expansion sleeves to expand and deform radially outwards.

[0010] Another method for anchoring submarine cables using a multi-point support system is provided. Based on the aforementioned multi-point support submarine cable anchoring device and an ROV robot equipped with a submarine drilling rig, camera, and control system, the method specifically includes the following steps: S1. Calculate the horizontal drag force and vertical lift force data of the cable anchoring device of the laid cable, calculate the resultant force vector, and adjust the angle of the rotating shaft through the angle adjustment structure so that the anchoring direction of the anchor assembly is opposite to the direction of the resultant force vector. S2. Control the ROV robot to drive the anchor bolt assembly to rotate towards the seabed. The base is set horizontally above the seabed soil, and the cable support is set vertically. The ROV extracts the output rotation torque in real time and calculates the undrained shear strength of the seabed soil at the current depth based on the output rotation torque. S3. Based on the undrained shear strength of the seabed soil, calculate the pull-out force data of the anchor bolt assembly after the expansion sleeve is deployed at the current depth in real time. S4. Calculate the safe pull-out threshold under the current sea conditions, compare the safe pull-out threshold with the tensile force in real time, repeat S2-S4 at a set frequency when the threshold is not exceeded, stop screwing the anchor bolt assembly when the tensile force exceeds the threshold, and trigger the expansion sleeve to unfold to complete the depth locking. As a preferred method, step S1 specifically includes the following steps: S1-1, Equipped with a multi-point support submarine cable anchoring device, which limits the axial position of the base on the rotating shaft by locking nuts and adjusting nuts, and controls the adjusting nut of the angle adjustment structure to make the sliding part of its second end slide into the rotating groove to allow the base to rotate freely around the rotating shaft; S1-2, The ROV robot initially screws the anchor assembly vertically into the seabed to stabilize the base. The cable is then engaged in the cable clamp, and horizontal drag force is applied to the seabed. and vertical lift Under the influence of the current, the base and cable support oscillate naturally with the current. After they come to a stop, the ROV's camera directly reads the tilt angle of the base relative to the vertical direction through the indexing caliper, thus obtaining the first natural equilibrium tilt angle. ; With the axis of rotation as the origin, establish the static equilibrium equations: ; ; The effective buoyancy of the base, cable support, and the portion of the cable held within the cable clamp in seawater; The total weight of the cable in the base, cable support, and the portion of the cable held within the cable clamp; The buoyancy force experienced by the base, cable support, and the portion of the cable clamped within the cable sleeve in seawater; The length of the vertical lever arm from the axis of rotation to the horizontal center of force on the cable; Simplifying, we get the first state equation: ; S1-3, Control the ROV robot to move along its robotic arm with... At collinear height positions, a standard horizontal thrust of known magnitude is applied in the same direction. The base continues to swing and reaches a new equilibrium. The ROV camera then reads the tilt angle again to obtain the second disturbance equilibrium tilt angle. ; Establish the static equilibrium equations after perturbation: ; Simplifying, we obtain state equation two: ; S1-4. Calculate the horizontal drag force by inversion using state equation one and state equation two. and vertical lift : ; .

[0011] As a preferred method, the following S1-5 is added after S1-4, specifically calculating the optimal anchorage angle according to the following formula. , That is, the angle between the anchoring direction of the anchor bolt and the vertical direction; .

[0012] As one of the preferred methods, in S2, the undrained shear strength of the seabed soil The following soil strength inversion model was used for calculation: ; in: The current depth obtained from real-time inversion Undrained shear strength of the seabed soil at the location; The output precession torque is provided as real-time feedback for the ROV. The outer diameter of the helical blade of the anchor bolt; The pitch of the helical blade; This is the preset correction coefficient for the precession resistance.

[0013] As one of the preferred methods, in S3, based on the undrained shear strength of the seabed soil Real-time calculation of the end bearing resistance provided by the expansion sleeve after expansion and deployment at the current depth L. Lateral frictional resistance between the outer wall of the propeller blades and the seabed sediment ,according to and The following equation for predicting pull-out force is established to calculate and obtain the pull-out force data in real time: ; in, This is the predicted pull-out force after the expansion sleeve expands and unfolds at the current screw depth L. This is the effective cross-sectional projected area of ​​the expansion sleeve after it has been unfolded. The bearing capacity coefficient is determined by the internal friction angle of the seabed soil. This is the equivalent outer diameter of the anchor bolt; The side friction reduction factor is obtained through the following steps: S3-10 Calculate the basic adhesion coefficient The foundation adhesion coefficient is determined by the undrained shear strength of the seabed soil. Segmentation determination: when The seabed soil is extremely soft silty clay. ; when The seabed soil is hard clay with a smooth shear failure surface. ; when When linear interpolation is used, ; S3-20, Introducing a precession perturbation correction factor ,right Make corrections and calculate according to the following formula. : ; in, For sensitivity of seabed soil, a value of 2 to 5 is generally used; The static consolidation time of the seabed soil after anchoring; The thixotropic recovery time constant of the soil; S3-30. Calculate the final reduction factor. : .

[0014] As one of the preferred methods, in S4, to ensure absolute safety, the anchor bolt provides an ultimate pull-out resistance. It must be greater than or equal to the total resultant force of the actual environment. Multiply by dynamic safety factor ,Right now: ; Substitute into S3 ,make = , The safety criticality equation is obtained as follows: ; For the optimal screw-in depth of the anchor bolt, when The depth L at which the minimum value is obtained; The dynamic safety factor for pull-out stability is determined based on the dynamic assessment of sea conditions, the degree of fatigue softening of the soil, and the risk of node routing. When the optimal precession depth is calculated The control system immediately sends an interrupt command to the ROV robot to stop the rotation, and uses the control moving rod to unfold the expansion sleeve to complete the anchor depth locking.

[0015] As a preferred embodiment, the following step is added after steps S1-5: S1-6. Reinstall the multi-point support submarine cable anchoring device, using locking nuts and adjusting nuts to limit the axial position of the base along the rotating shaft, and control the adjusting nut of the angle adjustment structure according to... This allows the indexing teeth at the first end to engage with the indexing slot, locking the anchoring direction of the anchor bolt assembly.

[0016] Because of the above-described solutions, one or more technical solutions provided in this application embodiment have at least the following technical effects or advantages: In one aspect, this multi-point supported submarine cable anchoring device can adjust the angle of the rotating shaft and thus the anchoring angle of the anchor bolt assembly through a scaled angle adjustment structure. This ensures that the anchoring direction is collinear and opposite to the resultant force of the external forces exerted on the cable anchoring device by the seabed environment. These external forces are mainly manifested by the horizontal drag force and vertical lift force exerted by the cable on the anchoring device. In this way, the expansion sleeve that unfolds after the anchor bolt is anchored mainly provides axial pull-out resistance, and the anchor bolt and expansion sleeve no longer need to withstand huge lateral shear forces, thereby preventing fatigue fracture of the anchor bolt assembly under cyclic loads.

[0017] On the other hand, the multi-point supported submarine cable anchoring device has a first form and a second form. In the first form, the sliding part of the second end of the adjusting nut in the angle adjustment structure slides with the rotating groove. The adjusting nut and the locking nut are only used to limit the axial position of the base on the rotating shaft, and do not restrict its circumferential position, that is, the base is allowed to rotate freely. The indexing teeth of the first end of the adjusting nut are arranged outward along the axial direction. At this time, it can be used as an external force load measuring tool. By pre-anchoring the anchor assembly vertically to the seabed, and then fixing the cable in the cable jacket, the base and cable support will swing naturally with the current. In this state, a static equilibrium equation can be constructed. Then, with the help of a standard force applied to the cable support, the base and cable support will be disturbed and oscillated. In this state, another static equilibrium equation can be constructed. By solving the two equations simultaneously, the external horizontal drag force and vertical lift force on the anchoring device can be calculated without the need for the measuring equipment of the cable laying vessel, such as the acoustic Doppler current meter (ADCP) or fixed sensing equipment to measure the external load on the anchoring device, which can significantly reduce construction costs and equipment costs.

[0018] In the second configuration, based on the optimal anchoring angle, the first end of the adjusting nut in the angle adjustment structure, with its indexing teeth facing inward, engages with the indexing groove in the rotating slide to lock the anchoring angle or anchoring direction of the anchor assembly. The adjusting nut and locking nut not only limit the axial position of the base on the rotating shaft but also lock the relative position of the base and the rotating shaft in the circumferential direction. During anchoring construction, the base is horizontally positioned above the seabed soil, and the cable support is vertically positioned. The anchor assembly is tilted and screwed into the target depth at the optimal anchoring angle. This effectively forms a wedge-shaped force transmission structure between the base and the anchor assembly, ensuring that the anchoring direction is collinear and opposite to the direction of the resultant force vector of the horizontal drag force and the vertical lift force. This prevents the anchor and expansion sleeve from bearing huge lateral shear forces and avoids breakage failure.

[0019] This cable anchoring device can switch between two forms, serving as both an anchoring node for cables and a force measuring tool similar to a flexible weather vane, facilitating underwater construction operations and significantly reducing construction costs.

[0020] On the other hand, using a multi-point support submarine cable anchoring method, after the anchoring direction of the anchor assembly is determined, an ROV robot is controlled to drive the anchor assembly to the seabed. By extracting the output rotation torque, the undrained shear strength of the seabed soil at the current depth is calculated in real time. This allows for the calculation and prediction of the pull-out force data of the anchor assembly after the expansion sleeve is deployed, until the predicted pull-out force data meets the safe pull-out threshold. Then, the rotation of the anchor assembly is stopped, and the expansion sleeve is deployed to complete the depth locking. In this way, there is no need to use a depth gauge or angle gauge to measure and calculate the pull-out force data. Instead, the ROV robot adaptively predicts and feeds back the pull-out force data during the anchor rotation process, and triggers the expansion sleeve deployment to complete the depth locking when the safety threshold is met. This not only greatly reduces the number of construction steps and simplifies the construction process, but also maximizes construction efficiency by using the optimal rotation depth while ensuring construction safety requirements, achieving intelligent and efficient construction operations. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings of the embodiments will be briefly described below. Obviously, the drawings described below only involve some embodiments of this application and should not be construed as limiting this application.

[0022] Figure 1 This is a schematic diagram of the cable anchoring device in this embodiment.

[0023] Figure 2 This is a schematic diagram of the cable anchoring device in the first configuration in this embodiment.

[0024] Figure 3 This is a schematic diagram of the cable anchoring device in the second configuration in this embodiment.

[0025] Figure 4 This is a schematic diagram of the assembly of some components of the cable anchoring device in the second configuration in this embodiment.

[0026] Figure 5 This is a schematic diagram showing the disassembled components of the cable anchoring device in the second configuration in this embodiment.

[0027] Figure 6 This is a cross-sectional schematic diagram of some components of the cable anchoring device in the second configuration in this embodiment.

[0028] Figure 7 This is a schematic diagram of the assembly of some components of the cable anchoring device in the first configuration in this embodiment.

[0029] Figure 8 This is a schematic diagram showing the disassembled components of the cable anchoring device in the first configuration in this embodiment.

[0030] Figure 9 This is a cross-sectional schematic diagram of some components of the cable anchoring device in the first configuration in this embodiment.

[0031] Figure 10 This is a schematic diagram of the anchor rod structure in this embodiment.

[0032] Figure 11 This is a cross-sectional schematic diagram of the anchor bolt in this embodiment.

[0033] Figure 12 yes Figure 11 A magnified view of part A in the middle.

[0034] Figure 13 yes Figure 11 A magnified view of part B in the middle.

[0035] Figure 14 This is a flowchart of the multi-point support submarine cable anchoring construction method in this embodiment.

[0036] Figure label: 100. Cable anchoring device; 1. Base; 11. Horizontal seat plate; 12. Side seat plate; 2. Cable bracket; 21. Bracket base; 22. Cable pole; 23. Cross frame; 231. Cable clamp; 3. Rotating shaft; 31. Angle adjustment structure; 311. External thread section; 312. Internal thread section; 313. Locking nut; 314. Rotating slide; 3141. Indexing slot; 316. Adjusting nut; 3161. Indexing tooth; 3162. Sliding part; 317. Cover plate groove; 318. Cover plate; 4. Anchor bolt assembly; 41. Row seat; 42. Fixing threaded sleeve; 43. Anchor bolt; 44. Rotating cap; 5. Locking structure; 51. Center threaded sleeve; 52. Moving rod; 521. External hexagonal block; 53. Extrusion head; 54. Wedge block; 55. Expansion sleeve. Detailed Implementation

[0037] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings, so as to more clearly understand the purpose, features and advantages of this invention. It should be understood that the embodiments shown in the drawings are not intended to limit the scope of this invention, but are only for illustrating the essential spirit of the technical solutions of this invention. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0038] Unless the context requires otherwise, throughout the specification and claims, the word “comprising” and its variations, such as “including” and “having”, shall be understood to have an open, inclusive meaning, that is, to be interpreted as “including, but not limited to”.

[0039] Throughout this specification, references to "an embodiment" or "an embodiment" indicate that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Therefore, the appearance of "in an embodiment" or "an embodiment" in various places throughout the specification does not necessarily refer to the same embodiment. Furthermore, a particular feature, structure, or characteristic may be combined in any manner in one or more embodiments.

[0040] The singular forms “a” and “the” used in this specification and the appended claims include plural references unless otherwise expressly stated herein. It should be noted that the term “or” is generally used to mean “and / or” unless otherwise expressly stated herein.

[0041] In the following description, in order to clearly demonstrate the structure and working method of the present invention, a number of directional terms will be used. However, terms such as "front", "back", "left", "right", "outside", "inside", "outward", "inward", "up", and "down" should be understood as convenient terms and not as limiting terms.

[0042] The implementation details of the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The following content is only for the convenience of understanding the implementation details and is not necessary for implementing this solution.

[0043] refer to Figures 1 to 14 This embodiment proposes a multi-point supported submarine cable anchoring device and anchoring construction method, aiming to solve the problem that existing cable anchoring devices and construction methods cannot adapt to complex seabed topography, such as landing sections, and cannot adapt to the actual direction of the resultant force of ocean currents. This results in the anchor bolt assembly being subjected to huge lateral shear forces, which easily leads to fatigue fracture or failure of weak areas of the anchor bolt structure, such as the expansion sleeve, under cyclic loads, reducing the service life of the anchoring device. This embodiment not only greatly reduces the lateral shear force borne by the anchor bolt assembly of the cable anchoring device, allowing the expansion sleeve to mainly bear the axial tensile force, giving full play to its pull-out resistance and improving the anchoring effect, but also allows the cable anchoring device to switch between two modes, namely anchoring mode and force measurement mode, realizing dual-purpose functionality, greatly simplifying the operation steps of anchoring construction, and reducing the cost of anchoring construction.

[0044] refer to Figures 1 to 9Specifically, the multi-point supported submarine cable anchoring device 100 includes a base 1 and a cable support 2 mounted on the base 1. The cable support 2 has one or more cable clamps 231. Side seats 12 are provided on both sides of the bottom of the base 1 along the cable length direction. The side seats 12 have rotating shaft holes extending along the cable length direction. A rotating shaft 3 is installed in the rotating shaft hole. An angle adjustment structure 31 is provided between the rotating shaft 3 and the base 1. An anchor bolt assembly 4 is installed at the outer end of each rotating shaft 3. The anchor bolt assembly 4 includes multiple anchor bolts 43 with expansion sleeves 55. The angle adjustment structure 31 includes an external thread section 311 and an internal thread section 311 mounted on the rotating shaft 3 and separated from both sides of the rotating shaft hole. 12; a locking nut 313 connected to the internal thread section 312; and an adjusting nut 316 connected to the external thread section 311; the outer end of the rotating shaft hole is coaxially provided with a rotating groove 314, the adjusting nut 316 is embedded in the rotating groove 314, the bottom surface of the rotating groove 314 is provided with an indexing groove 3141, the adjusting nut 316 has a first end and a second end along the axial direction, the first end has an indexing tooth 3161, the indexing tooth 3161 and the indexing groove 3141 are inserted and engaged along the axial direction to limit the angle of the rotating shaft 3, the second end has a sliding part 3162, the sliding part 3162 is slidably engaged with the rotating groove 314 to allow the base 1 to rotate freely.

[0045] Specifically, the base 1 includes a horizontal base plate 11 and side base plates 12 disposed on both sides of the bottom of the horizontal base plate 11. The side base plates 12 are vertically welded to the horizontal base plate 11, and the rotating shaft holes on the two side base plates 12 are aligned axially upward.

[0046] Specifically, the cable bracket 2 includes a bracket base 21 and a cable rod 22 disposed on the bracket base 21. The bracket base 21 is detachably connected to the horizontal plate 11 of the base 1. For example, in this embodiment, it is detachably connected to the horizontal plate 11 of the base 1 by nuts and bolts. In this way, the cable bracket 2 and the base 1 can be constructed separately, which can reduce the difficulty of construction.

[0047] Specifically, the cable support 2 further includes a horizontal frame 23 fixedly sleeved on the cable pole 22 in a straight line shape. In this embodiment, the horizontal frame 23 includes a fixed sleeve and horizontal frame rods extending laterally outward from opposite sides of the fixed sleeve. The fixed sleeve is vertically sleeved on the cable pole 22 and fixed with screws. The cable clamps 231 are disposed on the horizontal frame rods. In this embodiment, two cable clamps 231 are arranged on each horizontal frame rod. A total of four cables are laid on one device. The anchor bolt assemblies 4 on both sides are disposed on opposite sides of the base 1 along the cable length direction.

[0048] Specifically, considering the weight of the device and its torsional strength, the rotating shaft 3 is a hollow rotating shaft.

[0049] like Figures 7 to 9 As shown, the multi-point supported submarine cable anchoring device 100 has a first state and a second state during assembly. In the first state, the cable anchoring device 100 acts as a force measuring tool. Specifically, in the first state, the base 1, the rotating shaft 3, and the anchor bolt assembly 4 are assembled first. Specifically, the anchor bolt assembly 4 is first fixedly installed on the outer end of the rotating shaft 3. Then, the inner end of the rotating shaft 3 passes through the rotating shaft hole, so that the external thread section 311 is located on the outer end side of the rotating shaft hole, and the internal thread section 312 is located on the inner end side of the rotating shaft hole. Then, the angle adjustment structure 31 is assembled. Specifically, the adjusting nut 316 is first screwed onto the external thread section 311. At this time, the sliding part 3162 of the second end of the adjusting nut 316 faces the rotating shaft hole. Move the sliding groove 314, then move the rotating shaft 3 towards the inner end, driving the adjusting nut 316 to move until the sliding part 3162 is embedded in the rotating groove 314 and slides in cooperation with the rotating groove 314. Then, screw the locking nut 313 onto the internal thread section 312, limiting the axial position of the base 1 on the rotating shaft 3. At this time, the indexing teeth 3161 are not engaged with the indexing groove 3141, so the circumferential position of the base 1 is not restricted, that is, the base 1 is allowed to rotate freely. At this time, the first end of the adjusting nut 316, the indexing teeth 3161, is arranged axially towards the outer end, acting as a scale for balancing the tilt angle. At this time, it can be used as an external force load measuring tool. The specific usage method is as follows: Figure 2 As shown, by pre-anchoring the anchor assembly 4 vertically to the seabed, i.e., anchoring it to the seabed as shown in the figure, and then fixing the cable in the cable clamp 231, the base 1 and the cable support 2 will naturally swing with the current. In this state, a static equilibrium equation can be constructed. Then, by using a known standard force applied to the cable support 2, the base 1 and the cable support 2 will be disturbed and swung. In this state, another static equilibrium equation can be constructed. By solving the two equations simultaneously, the external horizontal drag force and vertical lift force on the cable anchoring device 100 can be calculated without the need for measuring equipment on the cable-laying vessel, such as an acoustic Doppler current meter (ADCP) or fixed sensing equipment to measure the external load on the anchoring device, which can significantly reduce construction and equipment costs.

[0050] like Figures 3 to 6As shown, in the second configuration, the cable anchoring device 100 acts as an anchoring node, ensuring that the expansion sleeve 55 mainly bears the axial tensile force after unfolding, or in other words, mainly provides pull-out resistance. Specifically, in the second configuration, the anchor rod assembly 4 is first fixedly installed on the outer end of the rotating shaft 3, and then the inner end of the rotating shaft 3 passes through the rotating shaft hole, so that the external thread section 311 is located on the outer end side of the rotating shaft hole, and the internal thread section 312 is located on the inner end side of the rotating shaft hole. Then, the angle adjustment structure 31 is assembled. Specifically, the adjusting nut 316 is first screwed onto the external thread section 311. At this time, the adjusting nut 31... The first end of the indexing tooth 3161 faces the rotating slide 314, and then the rotating shaft 3 moves towards the inner end, driving the adjusting nut 316 to move until the indexing tooth 3161 is engaged with the indexing groove 3141 in the rotating slide 314. Then the locking nut 313 is screwed onto the internal thread section 312 to limit the axial position of the base 1 on the rotating shaft 3. At this time, the indexing tooth 3161 and the indexing groove 3141 are combined to limit the circumferential position of the base 1. The relative angular position of the base 1 and the anchor rod assembly 4 around the axis of the rotating shaft 3 is also fixed.

[0051] It should be noted that here, the circumferential position between the adjusting nut 316 and the rotating shaft 3 is locked by the threaded engagement of the external thread section 311 and the adjusting nut 316. The base 1 and the adjusting nut 316 are rotated and locked by the insertion engagement of the indexing tooth 3161 and the indexing groove 3141. At the same time, the axial position of the base 1 along the rotating shaft 3 is locked by the tightening force applied axially by the adjusting nut 316 and the locking nut 313, thereby achieving the overall locking of the position of the base 1 on the rotating shaft 3. At this time, the cable anchoring device 100 is transformed into the anchoring node form described above.

[0052] Specifically, such as Figure 5 As shown, in this embodiment, a cover plate groove 317 is coaxially provided on the outer end of the rotating shaft hole on the side seat plate 12. The rotating slide groove 314 is provided on the bottom surface of the cover plate groove 317. In the second form, the adjusting nut 316 is completely embedded in the rotating slide groove 314. A cover plate 318 is provided in the cover plate groove 317. The cover plate 318 is fixed in the cover plate groove 317 by screws, which completes the encapsulation and protection of the adjusting nut 316. This prevents the adjusting nut 316 from slipping off along the external thread section 311 due to external force, causing the indexing tooth 3161 to disengage from the indexing groove 3141, thereby causing the anchoring node to fail.

[0053] In this embodiment, as Figure 3As shown, according to the optimal anchoring angle, the first end of the adjusting nut 316 in the angle adjustment structure 31 is inserted into the indexing groove 3141 in the rotating slide 314, which is oriented inward, to lock the anchoring angle or anchoring direction of the anchor rod assembly 4. The adjusting nut 316 and the locking nut 313 not only limit the axial position of the base 1 on the rotating shaft 3, but also lock the relative position of the base 1 and the rotating shaft 3 in the circumferential direction. During anchoring construction, the base 1 is set horizontally above the seabed soil, the cable bracket 2 is set vertically, and the anchor rod assembly 4 is tilted and screwed into the target depth at the optimal anchoring angle. In this way, a wedge-shaped force transmission structure is actually formed between the base 1 and the anchor rod assembly 4, so that the anchoring direction is collinear and opposite to the direction of the resultant force vector of the horizontal drag force and the vertical lift force, thereby avoiding the anchor rod 43 and the expansion sleeve 55 from bearing huge lateral shear force and preventing fracture failure.

[0054] The cable anchoring device 100 can switch between two forms, serving as both an anchoring node for cables and a force measuring tool similar to a flexible weather vane, facilitating seabed construction operations and significantly reducing construction costs.

[0055] In this embodiment, the multi-point supported submarine cable anchoring device 100 can adjust the angle of the rotating shaft 3 through the indexing angle adjustment structure 31, thereby adjusting the anchoring inclination angle of the anchor bolt assembly 4, so that the anchoring direction is collinear and opposite to the resultant force direction of the external force applied to the cable anchoring device 100 by the seabed environment. This external force is mainly manifested by the horizontal drag force and vertical lift force applied by the cable to the cable anchoring device 100. In this way, the expansion sleeve 55 that unfolds after the anchor bolt 43 is anchored mainly provides axial pull-out resistance, and the anchor bolt 43 and the expansion sleeve 55 no longer need to bear huge lateral shear force, thereby preventing the anchor bolt assembly 4 from fatigue fracture under reciprocating load.

[0056] like Figure 1 , Figures 10 to 13 As shown, in this embodiment, the anchor bolt assembly 4 includes a seat 41 fixedly disposed at the outer end of the rotating shaft 3. At least two anchor bolts 43 are provided on the seat 41. The two anchor bolts 43 are radially disposed on both sides of the rotating shaft 3. A vertical fixing thread sleeve 42 is provided on the seat 41. A helical blade is provided on the outer peripheral wall of the anchor bolt 43. The helical blade is screwed into the fixing thread sleeve 42. A rotating cap 44 is provided at the upper end of the anchor bolt 43.

[0057] Specifically, the mounting base 41 is provided with two fixing screw sleeves 42, which are symmetrically arranged about the corresponding rotating shaft 3. The mounting base 41 is provided with a rotating shaft clamp, and the rotating shaft 3 is clamped and fixed in the rotating shaft clamp. The bottom of the rotating shaft clamp is locked to the mounting base 41 by screws.

[0058] Specifically, the bottom end of the fixing sleeve 42 is welded to the seat 41, and the inside of the fixing sleeve 42 defines an anchor bolt hole that passes through the seat 41. The spiral blades of the corresponding anchor bolt 43 are screwed into the anchor bolt hole of the fixing sleeve 42.

[0059] like Figures 10 to 13 As shown, in this embodiment, the anchor rod 43 has a hollow inner cavity, and a locking structure 5 is provided in the hollow inner cavity. The locking structure 5 includes a central threaded sleeve 51 disposed in the rotating cap 44. A moving rod 52 is screwed into the central threaded sleeve 51. The moving rod 52 is vertically inserted into the hollow inner cavity. The upper end of the moving rod 52 is provided with an outer hexagonal block 521, and the lower end is provided with a conical extrusion head 53. An expansion sleeve 55 is provided on each of the radial sides of the lower end of the hollow inner cavity. A wedge block 54 is provided on the inner side of the expansion sleeve. The extrusion head 53 and the wedge block 54 abut against each other vertically. By moving the moving rod 52 downward spirally, the extrusion head 53 can be pushed downward to extrude the wedge block 54, thereby pushing the expansion sleeve 55 to expand and deform radially outward.

[0060] By rotating the rotating cap 44, the anchor rod 43 is driven to rotate synchronously, causing the anchor rod 43 to spiral into the seabed sand, thus anchoring the device at multiple points. This realizes the spiral anchoring function of the device, improving the device's anti-slip and anti-overturning capabilities on the seabed. The spiral installation can reduce the construction difficulty of seabed anchoring operations and improve operational efficiency.

[0061] By rotating the outer hexagonal block 521, the moving rod 52 moves vertically in a spiral motion, causing the extrusion head 53 to abut against the wedge block 54, thereby pushing the expansion sleeve 55 to expand and deform radially and embed into the surrounding sand. This achieves the anti-pull-out locking function of the device, increases the contact area and interlocking force between the anchor bolt assembly 4 and the seabed sand, and prevents the anchor bolt assembly 4 from loosening or being pulled out due to the reciprocating load brought by ocean currents and tides.

[0062] like Figure 14 As shown in the figure, this embodiment also proposes a multi-point supported submarine cable anchoring construction method, based on the multi-point supported submarine cable anchoring device 100 and an ROV robot equipped with a submarine drilling rig, camera, and control system (not shown in the figure), specifically including the following steps: S1. Calculate the horizontal drag force and vertical lift force data of the cable anchoring device 100 for the laid cable, calculate the resultant force vector, and adjust the angle of the rotating shaft 3 through the angle adjustment structure 31 so that the anchoring direction of the anchor assembly 4 is opposite to the direction of the resultant force vector. S2. Control the ROV robot to drive the anchor bolt assembly 4 to rotate towards the seabed. The base 1 is set horizontally above the seabed soil, and the cable bracket 2 is set vertically. The ROV extracts the output rotation torque in real time and calculates the undrained shear strength of the seabed soil at the current depth in real time based on the output rotation torque. S3. Based on the undrained shear strength of the seabed soil, calculate the pull-out force data of the anchor bolt assembly 4 after the expansion sleeve 55 is deployed at the current depth in real time. S4. Repeat S2-S3 at a set frequency and calculate the safe pull-out threshold under the current sea state. Compare the safe pull-out threshold with the pull-out force in real time. When the pull-out force exceeds the threshold, stop screwing in the anchor bolt assembly 4 and trigger the expansion sleeve 55 to unfold and complete the depth locking.

[0063] In this embodiment, using this multi-point support submarine cable anchoring construction method, after the anchoring direction of the anchor assembly 4 is determined, the ROV robot drives the anchor assembly 4 to rotate towards the seabed. By extracting the output rotation torque, the undrained shear strength of the seabed soil at the current depth is calculated in real time. This allows for the calculation and prediction of the pull-out force data of the anchor assembly 4 after the expansion sleeve 55 is deployed. The pull-out force data continues until it meets the safe pull-out threshold. Then, the rotation of the anchor assembly 4 is stopped, and the expansion sleeve 55 is deployed to complete the depth locking. This eliminates the need for depth gauges, angle gauges, and land exploration equipment to measure and calculate pull-out force data. Instead, the ROV robot adaptively predicts and feeds back the pull-out force data during the anchor rotation process, triggering the expansion sleeve 55 to complete the depth locking when the safety threshold is met. This significantly reduces construction steps and simplifies the construction process. Furthermore, while ensuring construction safety requirements are met, the optimal rotation depth maximizes construction efficiency, achieving intelligent and efficient construction operations.

[0064] In addition, by using the output rotary torque of the ROV drilling rig to calculate the undrained shear strength of the seabed soil and predict the tensile force data in real time, it is possible to sense the anchorage depth while drilling, which greatly reduces the survey cost and construction period of the cable laying project.

[0065] Specifically, S1 includes the following steps: S1-1, as shown Figure 2 As shown, a multi-point support submarine cable anchoring device 100 is equipped with a locking nut 313 and an adjusting nut 316 to limit the axial position of the base 1 on the rotating shaft 3 and control the adjusting nut 316 of the angle adjustment structure 31 so that the sliding part 3162 at the second end of the adjusting nut 316 slides into the rotating groove 314 to allow the base 1 to rotate freely around the rotating shaft 3. S1-2, as shown Figure 2 As shown, the ROV robot initially screws the anchor assembly 4 vertically into the seabed to stabilize the base 1, and the cable is inserted into the cable clamp 231, under the horizontal drag force on the seabed. and vertical lift Under the influence of the current, the base 1 and cable bracket 2 naturally oscillate with the current. After they come to a stop, the ROV's camera directly reads the tilt angle of the base 1 relative to the vertical direction through the indexing caliper 3161, thus obtaining the first natural equilibrium tilt angle. ,like Figure 2 As shown; With the axis of rotation as the origin, and based on the principle of torque balance, establish the static equilibrium equations: ; ; The effective buoyancy of the partial cable held in the base 1, cable bracket 2 and cable clamp 231 in seawater, where the partial cable refers to the cable between two adjacent cable anchoring devices 100 along the cable length direction. The total weight of the local cable held in the base 1, cable bracket 2, and cable clamp 231; The buoyancy force experienced by the cable in seawater in the base, cable support 2, and cable clamp 231. The length of the vertical lever arm from the axis of shaft 3 to the horizontal center of force on the cable, such as Figure 2 As shown; Simplifying, we get the first state equation: ; S1-3, Control the ROV robot to move along its robotic arm with... At collinear height positions, a standard horizontal thrust of known magnitude is applied in the same direction. The base 1 continues to swing and reaches a new equilibrium. The ROV camera then reads the tilt angle again to obtain the second disturbance equilibrium tilt angle. ; Establish the static equilibrium equations after perturbation: ; Simplifying, we obtain state equation two: ; S1-4. The horizontal drag force and vertical lift force are calculated by inversion using state equation one and state equation two: ; .

[0066] Furthermore, S1-5 is added after S1-4, specifically calculating the optimal anchorage angle according to the following formula. , That is, the angle between the anchoring direction of anchor bolt 43 and the vertical direction; .

[0067] Furthermore, after S1-5, the following steps are added: S1-6. Reinstall the multi-point support submarine cable anchoring device 100, using the locking nut 313 and adjusting nut 316 to limit the axial position of the base 1 along the rotating shaft 3, and control the adjusting nut 316 of the angle adjustment structure 31 according to... The indexing tooth 3161 at its first end is inserted into the indexing groove 3141 to lock the anchoring direction of the anchor bolt assembly 4.

[0068] In this embodiment, the control system will solve the and Input directly to the optimal anchorage angle The calculation equations, as well as the subsequent critical equations, are used to calculate and determine the optimal precession depth. .

[0069] Specifically, in S2, the undrained shear strength of the seabed soil The following soil strength inversion model was used for calculation: ; in: The current depth obtained from real-time inversion Undrained shear strength of the seabed soil at the location; The output precession torque is provided as real-time feedback for the ROV. The outer diameter of the helical blade of the anchor bolt; The pitch of the helical blade; This is a preset correction coefficient for the spiral or cutting resistance.

[0070] It should be noted that when the auger blades cut into the soft seabed soil, the ROV drilling rig's output torque is mainly used to overcome the shear failure of the soil. According to the law of conservation of energy, the work done by the ROV drilling rig in one revolution is equal to the plastic deformation energy consumed by the auger blades displacing the soil. Therefore, the torque is positively correlated with the undrained shear strength of the soil at the current depth. This mechanical relationship is used to obtain the soil strength inversion model.

[0071] Undrained shear strength Determined by the properties of the seabed soil itself, during the screwing-in process of anchor bolt 43, regardless of whether the expansion sleeve 55 expands and unfolds, the undrained shear strength of the seabed soil remains constant. Unchanged, the control system receives Then, by combining the outer diameter and pitch of the spiral blades of anchor bolt 43, the shear strength of the seabed soil at the current depth is calculated using the cutting energy conservation equation.

[0072] Specifically, in S3, based on the undrained shear strength of the seabed soil Real-time calculation of the end bearing resistance provided by the expansion sleeve after expansion and deployment at the current depth L. Lateral frictional resistance between the outer wall of the propeller blades and the seabed sediment ,according to and The following equation for predicting pull-out force is established to calculate and obtain the pull-out force data in real time: ; in, This is the predicted pull-out force after the expansion sleeve expands and unfolds at the current screw depth L. This is the effective cross-sectional projected area of ​​the expansion sleeve after it has been unfolded. The bearing capacity coefficient is determined by the internal friction angle of the seabed soil. This is the equivalent outer diameter of the anchor bolt; The side friction reduction factor is obtained through the following steps: S3-10 Calculate the basic adhesion coefficient The foundation adhesion coefficient is determined by the undrained shear strength of the seabed soil. Segmentation determination: when The seabed soil is extremely soft silty clay. ; when The seabed soil is hard clay with a smooth shear failure surface. ; when When linear interpolation is used, ; S3-20, Introducing a precession perturbation correction factor ,right Make corrections and calculate according to the following formula. : ; in, For sensitivity of seabed soil, a value of 2 to 5 is generally used; The static consolidation time of the seabed soil after anchoring; The thixotropic recovery time constant of the soil; S3-30. Calculate the final reduction factor. : 。

[0073] In this embodiment, the control system retrieves the inherent geometric dimensions of the cable anchoring device 100 when the expansion sleeve 55 is in the expanded and unfolded state, that is, the effective projected area formed along the axial direction after the expansion sleeve 55 is fully expanded. Then, the inverted undrained shear strength of the seabed soil is obtained. Substituting this into the ultimate pull-out mechanical model in the unfolded state, the control system calculates the predicted pull-out force: This enables real-time prediction of tensile pull-out force data.

[0074] It should be noted that the calculation of end bearing capacity generally needs to consider the effective unit weight term. However, in the actual submarine cable laying area, most of the soil is deep-sea silty soft clay, and the internal friction angle of the soil is close to 0. Since the effective unit weight of soft clay is extremely small, the pull-out force generated by this term can be ignored compared with the soil cohesion. Therefore, the above formula ignores the calculation of soil unit weight.

[0075] Specifically, to ensure absolute safety, the anchor bolt provides the ultimate tensile pull-out force. It must be greater than or equal to the total resultant force of the actual environment. Multiply by dynamic safety factor ,Right now: ; Substitute into S3 ,make = , The safety criticality equation is obtained as follows: ; The optimal depth for screwing in the anchor bolt, i.e., when The depth L at which the minimum value is obtained; The dynamic safety factor for pull-out stability is determined based on the dynamic assessment of sea conditions, the degree of fatigue softening of the soil, and the risk of node routing. here, : in, The basic safety factor is determined based on different sea state classifications for different operations: Under normal sea conditions, take ; Under extreme typhoon / storm sea conditions, a certain degree of plastic deformation is permissible. .

[0076] This is the cyclic load softening amplification factor, used to compensate for the decrease in shear strength of seabed sediment caused by the cyclic load of ocean currents. in: The number of wave / current circulation disturbances during the design life; The fatigue attenuation coefficient of the seabed soil is typically between 0.05 and 0.15. The risk coefficient for a submarine cable route node is determined by assigning a weighted value based on the importance of that anchor point within the entire submarine cable route. If the device is installed on a straight section of a flat seabed, the risk is low. ; If the device is installed on a suspended section, at a sharp bend in the route, or on the landing section, the stress concentration will be severe, and failure will lead to cable breakage. .

[0077] When the optimal precession depth is calculated The control system immediately sends an interrupt command to the ROV robot to stop the rotation, and uses the control moving rod 52 to unfold the expansion sleeve 55 to complete the depth locking of the anchor rod 43.

[0078] In summary, the above embodiments first acquire marine environmental load data, calculate the resultant force vector to determine the optimal anchoring angle for reducing the lateral shear force of the anchor bolt 43, and then control the ROV robot to screw the anchor bolt assembly 4 at the optimal anchoring angle. By extracting the screwing torque in real time, the undrained shear strength of the seabed soil is calculated using an inversion model, eliminating the need for independent geological exploration. Then, based on the side friction reduction and end bearing model, the ultimate pull-out force at the current depth is dynamically predicted. Finally, a dynamic safety factor including wave fatigue and routing risk is introduced. When the predicted pull-out force meets the safe pull-out threshold, drilling is stopped and the expansion sleeve 55 is deployed. Through the above anchoring construction method, the construction cost is significantly reduced, over-drilling or insufficient pull-out force is avoided, and the long-term operational safety of the submarine cable is ensured.

[0079] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or basic characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects. The scope of the invention is defined by the appended claims rather than the foregoing description. Therefore, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention, and no reference numerals in the claims should be construed as limiting the scope of the claims.

[0080] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A multi-point supported submarine cable anchoring device, comprising a base and a cable support mounted on the base, wherein the cable support is provided with one or more cable clamps, and side seats are provided on both sides of the bottom of the base along the cable length direction. Each side seat has a pivot hole extending along the cable length direction, and a pivot is installed in the pivot hole. An angle adjustment structure is provided between the pivot and the base. An anchor bolt assembly is installed at the outer end of each pivot, and the anchor bolt assembly includes multiple anchor bolts with expansion sleeves. The angle adjustment structure includes: An external thread section and an internal thread section are provided on the rotating shaft and separated on both sides of the rotating shaft hole; A locking nut connected to the internal thread section; An adjusting nut connected to the external thread section; The outer end of the rotating shaft hole is coaxially provided with a rotating groove, and the adjusting nut is embedded in the rotating groove. The bottom surface of the rotating groove is provided with an indexing groove. The adjusting nut has a first end and a second end along the axial direction. The first end has an indexing tooth, which is inserted into the indexing groove along the axial direction to limit the angle of the rotating shaft. The second end has a sliding part, which slides with the rotating groove to allow the base to rotate freely.

2. A multi-point supported subsea cable anchoring device according to claim 1, characterised in that, The anchor bolt assembly includes a seat fixedly disposed at the outer end of the rotating shaft. At least two anchor bolts are provided on the seat, and the two anchor bolts are radially disposed on both sides of the rotating shaft. A vertical fixing threaded sleeve is provided on the seat. A helical blade is provided on the outer peripheral wall of the anchor bolt. The helical blade is screwed into the fixing threaded sleeve. A rotating cap is provided at the upper end of the anchor bolt.

3. A multi-point supported subsea cable anchoring device according to claim 2, characterised in that, The anchor rod has a hollow inner cavity, and a locking structure is provided inside the hollow inner cavity. The locking structure includes a central threaded sleeve disposed inside a rotating cap. A movable rod is screwed into the central threaded sleeve. The movable rod is vertically inserted into the hollow inner cavity. The upper end of the movable rod is provided with an outer hexagonal block, and the lower end is provided with a conical extrusion head. An expansion sleeve is provided on each of the radial sides of the lower end of the hollow inner cavity. A wedge is provided on the inner side of the expansion sleeve. The extrusion head and the wedge abut against each other vertically. By moving the movable rod downward spirally, the extrusion head can be pushed downward to extrude the wedge, thereby pushing the expansion sleeve to expand and deform radially outward.

4. A multi-point supported submarine cable anchoring construction method, based on the multi-point supported submarine cable anchoring device as described in claim 3 and an ROV robot equipped with a submarine drilling rig, camera, and control system, specifically includes the following steps: S1. Calculate the horizontal drag force and vertical lift force data of the cable anchoring device of the laid cable, calculate the resultant force vector, and adjust the angle of the rotating shaft through the angle adjustment structure so that the anchoring direction of the anchor assembly is opposite to the direction of the resultant force vector. S2. Control the ROV robot to drive the anchor bolt assembly to rotate towards the seabed. The base is set horizontally above the seabed soil, and the cable support is set vertically. The ROV extracts the output rotation torque in real time and calculates the undrained shear strength of the seabed soil at the current depth based on the output rotation torque. S3. Based on the undrained shear strength of the seabed soil, calculate the pull-out force data of the anchor bolt assembly after the expansion sleeve is deployed at the current depth in real time. S4. Calculate the safe pull-out threshold under the current sea conditions, compare the safe pull-out threshold with the tensile force in real time, repeat S2-S4 at a set frequency when the threshold is not exceeded, stop screwing the anchor bolt assembly when the tensile force exceeds the threshold, and trigger the expansion sleeve to unfold to complete the depth locking.

5. The multi-point support submarine cable anchoring construction method according to claim 4, characterized in that, S1 specifically includes the following steps: S1-1, Equipped with a multi-point support submarine cable anchoring device, which limits the axial position of the base on the rotating shaft by locking nuts and adjusting nuts, and controls the adjusting nut of the angle adjustment structure to make the sliding part of its second end slide into the rotating groove to allow the base to rotate freely around the rotating shaft; S1-2, The ROV robot initially screws the anchor assembly vertically into the seabed to stabilize the base. The cable is then engaged in the cable clamp, and horizontal drag force is applied to the seabed. and vertical lift Under the influence of the current, the base and cable support oscillate naturally with the current. After they come to a stop, the ROV's camera directly reads the tilt angle of the base relative to the vertical direction through the indexing caliper, thus obtaining the first natural equilibrium tilt angle. ; With the axis of rotation as the origin, establish the static equilibrium equations: ； ； The effective buoyancy of the base, cable support, and the portion of the cable held within the cable clamp in seawater; The total weight of the cable in the base, cable support, and the portion of the cable held within the cable clamp; The buoyancy force experienced by the base, cable support, and the portion of the cable clamped within the cable sleeve in seawater; The length of the vertical lever arm from the axis of rotation to the horizontal center of force on the cable; Simplifying, we get the first state equation: ; S1-3, Control the ROV robot to move along its robotic arm with... At collinear height positions, a standard horizontal thrust of known magnitude is applied in the same direction. The base continues to swing and reaches a new equilibrium. The ROV camera then reads the tilt angle again to obtain the second disturbance equilibrium tilt angle. ; Establish the static equilibrium equations after perturbation: ； Simplifying, we obtain state equation two: ; S1-4. Calculate the horizontal drag force by inversion using state equation one and state equation two. and vertical lift : ； 。 6. The multi-point supported submarine cable anchoring construction method according to claim 5, characterized in that, Add the following S1-5 after S1-4, specifically calculating the optimal anchorage angle according to the following formula. , That is, the angle between the anchoring direction of the anchor bolt and the vertical direction; 。 7. The multi-point support submarine cable anchoring construction method according to any one of claims 4 to 6, characterized in that, In S2, the undrained shear strength of the seabed soil The following soil strength inversion model was used for calculation: ； in: The current depth obtained from real-time inversion Undrained shear strength of the seabed soil at the location; The output precession torque is provided as real-time feedback for the ROV. The outer diameter of the helical blade of the anchor bolt; The pitch of the helical blade; This is the preset correction coefficient for the precession resistance.

8. The multi-point supported submarine cable anchoring construction method according to claim 7, characterized in that, In S3, based on the undrained shear strength of the seabed soil Real-time calculation of the end bearing resistance provided by the expansion sleeve after expansion and deployment at the current depth L. Lateral frictional resistance between the outer wall of the propeller blades and the seabed sediment ,according to and The following equation for predicting pull-out force is established to calculate and obtain the pull-out force data in real time: ； in, This is the predicted pull-out force after the expansion sleeve expands and unfolds at the current screw depth L. This is the effective cross-sectional projected area of ​​the expansion sleeve after it has been unfolded. The bearing capacity coefficient is determined by the internal friction angle of the seabed soil. This is the equivalent outer diameter of the anchor bolt; The side friction reduction factor is obtained through the following steps: S3-10 Calculate the basic adhesion coefficient The foundation adhesion coefficient is determined by the undrained shear strength of the seabed soil. Segmentation determination: when The seabed soil is extremely soft silty clay. ; when The seabed soil is hard clay with a smooth shear failure surface. ; when When linear interpolation is used, ; S3-20, Introducing a precession perturbation correction factor ,right Make corrections and calculate according to the following formula. : ； in, For sensitivity of seabed soil, a value of 2 to 5 is generally used; The static consolidation time of the seabed soil after anchoring; The thixotropic recovery time constant of the soil; S3-30. Calculate the final reduction factor. : 。 9. The multi-point support submarine cable anchoring construction method according to claim 8, characterized in that, In S4, to ensure absolute safety, the anchor bolt provides the ultimate pull-out resistance. It must be greater than or equal to the total resultant force of the actual environment. Multiply by dynamic safety factor ,Right now: ； Substitute into S3 ,make = , The safety criticality equation is obtained as follows: ； The optimal depth for screwing in the anchor bolt, i.e., when The depth L at which the minimum value is obtained; The dynamic safety factor for pull-out stability is determined based on the dynamic assessment of sea conditions, the degree of fatigue softening of the soil, and the risk of node routing. When the optimal precession depth is calculated The control system immediately sends an interrupt command to the ROV robot to stop the rotation, and uses the control moving rod to unfold the expansion sleeve to complete the anchor depth locking.

10. The multi-point supported submarine cable anchoring construction method according to claim 6, characterized in that, Following S1-5, add the following steps: S1-6. Reinstall the multi-point support submarine cable anchoring device, using locking nuts and adjusting nuts to limit the axial position of the base along the rotating shaft, and control the adjusting nut of the angle adjustment structure according to... This allows the indexing teeth at the first end to engage with the indexing slot, locking the anchoring direction of the anchor bolt assembly.

Images