CN118889311A - A device and method for preventing anchor damage of submarine cable at mud-entering end - Google Patents

Abstract

The present invention provides a device and method for preventing anchor damage at the end of a submarine cable entering mud, wherein the method comprises S1, determining the side length L of the anchor damage prevention pile according to the diameter d of the submarine cable to be protected; S2, arranging a plurality of anchor damage prevention piles on both sides of the submarine cable to be protected; S3, determining the spacing Lx between the anchor damage prevention piles in the direction perpendicular to the water flow and the spacing Ly between the anchor damage prevention piles along the water flow according to the side length L of the anchor damage prevention piles; S4, adjusting the positions of the plurality of anchor damage prevention piles according to the spacing Lx between the anchor damage prevention piles in the direction perpendicular to the water flow and the spacing Ly between the anchor damage prevention piles along the water flow. The present invention can effectively prevent the anchor of a ship from damaging the submarine cable.

Description

A device and method for preventing anchor damage of submarine cable at mud-entering end

Technical Field

The present invention relates to the technical field of submarine cable protection, and in particular to a device and method for preventing anchor damage to a submarine cable at a mud-entering end.

Background Art

Due to work needs, there are often working ships or maintenance ships docked next to wind turbines, and the anchors of ships are very likely to damage the submarine cables during movement. At present, there are few devices to prevent anchor damage to submarine cables at the mud-entering end. Most of the submarine cables in wind farms are directly extended from the wind turbines and laid on the seabed. Some existing methods are mainly based on warnings, which issue warnings when the ship approaches the wind turbine. In fact, the staff usually ignores the warnings because the warning device can only detect whether it is approaching. Whether it hooks the submarine cable or not, the alarm will be triggered. The anchor of the docked ship may not hook the submarine cable, which leads to negligence of the crew.

For the protection of some special sections with shallow burial depth or exposed sections of submarine cables, most methods include throwing stones, covering with sandbags, placing concrete chain blocks, etc., which are easily affected by hydrology and have little effect on protecting the connection with anchors and cannot meet the requirements of high-quality, long-term submarine cable protection.

Riprap protection: For areas where the seabed is too hard to be protected by burial, the method used is to riprap the submarine cable to prevent damage. That is, gravel with reasonable grading is thrown around the submarine cable through specific construction equipment to form a protective layer. It is currently the most widely used. When performing riprap protection, the following variables need to be considered: changes in the thickness of the riprap layer, stone characteristics, burial shape, burial range, anchor damage intrusion of anchors of different weights, and the initial intrusion speed of the anchor during the anchor damage process. Although this protection method can effectively keep the pipeline stationary, avoid scouring and suspension, and protect the pipeline from being affected by human factors such as anchors, it is low in cost and simple in construction method; however, if improper measures are taken and the pipeline cannot be well restricted, the pipeline will rub against the surrounding stones, resulting in more serious damage; and water will also flow into the gaps between the stones, forming a flow between the gaps, which will continuously wash out fine sand or stones, and eventually lead to the failure of the protection measures; at the same time, at the edge of the riprap layer, scouring will also occur around these stones, resulting in instability and deformation.

Support fixed protection: For this type of device, some device or structure is usually used to fix the submarine cable underwater. Generally speaking, this type of fixing effect is good; but once it involves underwater drilling or piling fixation, the cost will be greatly increased, and it is difficult to use on a large scale. It is also difficult to fix in the face of severe storm surges, and it is rarely used in practice. The method without piling is shown in the figure below, which is to use mud and sand to clamp the submarine cable. This method has a poor fixing effect and will fail if the water flow is fast or the operation time is slightly longer.

The utility model with the publication number CN216056258U discloses an inserted submarine cable anchoring protection device, comprising a U-shaped protective shell body, two anti-sinking resistance baffles are arranged on the inner side of the lower part of the protective shell body, a gap larger than the diameter of the submarine cable is formed between the two resistance baffles, a drainage hole is arranged on the upper part of the protective shell body, and insertion parts for inserting into the seabed are arranged at the lower ends of both sides of the protective shell body. However, the above-mentioned inserted submarine cable anchoring protection device uses mud and sand to jam the submarine cable, and will fail if the water flow is fast or the operation time is slightly longer.

Summary of the invention

The object of the present invention is to solve the defects in the prior art and provide a device and method for preventing anchor damage to a submarine cable at the mud-entering end, which can effectively prevent the anchor of a ship from damaging the submarine cable.

To achieve the above-mentioned purpose, the present invention provides an anti-anchor damage device for a submarine cable at the mud-entering end, comprising a plurality of anti-anchor damage piles arranged opposite to each other on both sides of the submarine cable to be protected, wherein adjacent anti-anchor damage pile devices arranged perpendicular to the water flow direction are connected by a connecting rope, a accommodating cavity for placing materials is provided in the anti-anchor damage pile, and a plurality of resistance-increasing parts are provided on the side walls of the anti-anchor damage pile.

Optionally, the anti-anchoring pile is provided with a plurality of connecting columns, and the connecting rope is connected to the anti-anchoring pile via the connecting columns.

Optionally, the anti-anchoring pile includes a pile body and a pile cover, the pile cover is connected to the pile body, and the accommodating cavity is arranged in the pile body.

Optionally, a plurality of drainage holes are provided at the bottom of the pile body, and a plurality of exhaust holes are provided on the pile cover.

The present invention also provides a method for preventing anchor damage to a submarine cable at a mud-entering end, comprising the following steps:

S1. Determine the side length L of the anchor damage prevention pile according to the diameter d of the submarine cable to be protected;

S2. Install several anchor damage prevention piles on both sides of the submarine cable to be protected;

S3, according to the side length L of the anti-anchor damage pile, determine the spacing Lx between the anti-anchor damage piles perpendicular to the water flow direction and the spacing Ly between the anti-anchor damage piles along the water flow direction;

S4. Adjust the positions of several anti-anchoring piles according to the spacing Lx between the anti-anchoring piles in the direction perpendicular to the water flow and the spacing Ly between the anti-anchoring piles along the water flow.

The present invention sets obstacles on both sides of the submarine cable through the above-mentioned anchor damage prevention method for the submarine cable at the mud-entering end, blocks the anchor in advance before it approaches the submarine cable, thereby preventing the submarine cable from being hooked. At the same time, considering the influence of the anchor damage prevention piles on the flow field, the spacing of the anchor damage prevention piles is reasonably set to minimize the adverse effect of the anchor damage prevention piles, and at the same time, it can effectively reduce the scouring of mud and sand around the submarine cable, which can effectively protect the submarine cable from damage by the anchor for a long time, while taking into account the cost and construction process.

Optionally, in S1, the formula for determining the side length L of the anti-anchor pile is:

Optionally, in S3, the formula for determining the spacing Lx between the anti-anchor damage piles perpendicular to the water flow direction is:

Lx=10L _.

Optionally, in S3, the formula for determining the spacing Ly between the joint defense anchor piles is:

Ly＝15L

Optionally, before step S1, the method further includes step S0, determining a reference range of submarine cable diameter according to the resistance encountered by the anti-anchor pile when being hooked in the mud and sand, and judging whether the diameter d of the submarine cable to be protected is within the range;

If the diameter of the submarine cable to be protected is too small, take the minimum value in the reference range of the submarine cable diameter for subsequent steps; if the diameter of the submarine cable to be protected is too large, take the maximum value in the reference range of the submarine cable diameter for subsequent steps.

Optionally, in step S0, the formula for the resistance to the movement of the anti-anchor pile when being hooked in the mud is:

Where C refers to the resistance coefficient in the sediment, ρ is the density of the sediment, v is the movement speed, and s is the cross-sectional area of the anti-anchor pile;

According to the cross-sectional area of the anti-anchor pile, the reference range of the submarine cable diameter is obtained.

Beneficial effects:

The present invention sets obstacles on both sides of the submarine cable through the above-mentioned anchor damage prevention method for the submarine cable at the mud-entering end, blocks the anchor in advance before it approaches the submarine cable, thereby preventing the submarine cable from being hooked. At the same time, considering the influence of the anchor damage prevention piles on the flow field, the spacing of the anchor damage prevention piles is reasonably set to minimize the adverse effect of the anchor damage prevention piles, and at the same time, it can effectively reduce the scouring of mud and sand around the submarine cable, which can effectively protect the submarine cable from damage by the anchor for a long time, while taking into account the cost and construction process.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

FIG1 is a top view of the distribution of anchor damage prevention piles in the method for preventing anchor damage of a submarine cable at the mud end disclosed in the present invention;

FIG2 is a diagram showing the variation of the scouring depth of the anchor damage prevention piles arranged along the water flow direction in the method for preventing anchor damage at the mud-entering end of a submarine cable disclosed in the present invention;

3 is a diagram showing the variation of the scouring depth of the anchor damage prevention piles arranged perpendicular to the water flow direction in the method for preventing anchor damage at the mud-entering end of a submarine cable disclosed in the present invention;

4 is a schematic diagram of the scouring length and scouring width of the anchor damage prevention piles arranged along the water flow direction and the anchor damage prevention piles arranged perpendicular to the water flow direction in the method for preventing anchor damage of the submarine cable at the mud end disclosed in the present invention;

5 is a diagram showing the changes in the scouring length of the anchor damage prevention piles arranged along the water flow direction and the scouring width of the anchor damage prevention piles arranged perpendicular to the water flow direction in the method for preventing anchor damage at the mud-entering end of a submarine cable disclosed in the present invention;

6 is a diagram showing changes in the scouring width of the anchor damage prevention piles arranged along the water flow direction and the scouring length of the anchor damage prevention piles arranged perpendicular to the water flow direction in the method for preventing anchor damage at the mud-entering end of a submarine cable disclosed in the present invention;

7 is a structural diagram of the anti-anchor damage pile in the anti-anchor damage device for submarine cables at the mud end disclosed in the present invention from a first perspective;

FIG8 is a structural diagram of the second viewing angle of the anti-anchor damage device for the submarine cable at the mud entry end disclosed by the present invention;

FIG. 9 is a structural diagram of the third viewing angle of the mud-entering end submarine cable anchor damage prevention device disclosed in the present invention.

Reference numerals:

1. Submarine cable to be protected; 2. Anti-anchor pile; 3. Pile body; 4. Drain hole; 5. Pile cover; 6. Exhaust hole; 7. Accommodation cavity; 8. Connecting column; 9. Resistance increasing component; 10. Connecting rope; 11. Wind turbine.

The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with the implementation methods and with reference to the accompanying drawings.

DETAILED DESCRIPTION

Referring to FIG. 1 , in actual arrangement, a plurality of anti-anchoring piles 2 are arranged in two positions: along the water flow direction and perpendicular to the water flow direction.

Existing literature: Sacrificial piles as a countermeasure against local scouraround underwater pipelines. Forough Raeisi, Seyed Mohammad Ali Zomorodian, Masih Zolghadr, Hazi Mohammad Azamathulla. Water Science and Engineering, Volume 17, Issue 2, 2024, Pages 187-196, ISSN 1674-2370 records the following:

For the anchor-damage prevention piles arranged along the direction of the water flow, see Figure 2. The horseshoe vortex in front of the rear pile will cause damage due to insufficient space in front of the pile. Only when the gap ratio is greater than 3D (D is the diameter of the pile, which is equivalent to the side length L of the anchor-damage prevention pile in the present invention), the influence of the upstream tail vortex will be reduced to cause a horseshoe vortex to appear in front of the downstream pile. When the spacing ratio is 2D, the front pile has the largest scouring depth, which becomes 1.3D. After it is greater than 10D, the scouring depth is the same as that of a single pile; the scouring depth of the rear pile is always smaller, and the scouring depth increases before the ratio is 5D, and decreases after 5D. In order to ensure the stability of the pile, the surrounding scouring depth is as small as possible; in order to reduce the impact on the submarine cable, it is best that there is no scouring pit between the two piles (point B).

For the anchor damage prevention piles set perpendicular to the water flow direction, see Figure 3. When the spacing ratio is 0, it can be regarded as a whole, and the scouring depth is also greater at 1.9S. When the spacing ratio is 7, the scouring depth in front of the pile is the same as that of the single pile; between the two piles, when the spacing ratio is 2, the scouring depth is the same as that of the single pile, and then it decreases continuously. When the ratio is 10, there is no scouring between the two piles. The scouring pits around the piles and the scouring pits in the middle will affect their stability.

See Figure 4-6, the scouring range changes with different spacing and pile diameter ratios. The left side of Figure 4 shows the anti-anchor damage piles set along the water flow direction, and the right side shows the anti-anchor damage piles set perpendicular to the water flow direction.

For the anchor damage prevention piles set along the water flow direction, the scour length Lx increases with the spacing ratio, and the scour width Ly reaches the maximum at 0.5, which is 3D.

For the anchor damage prevention piles set perpendicular to the water flow direction, the scour length Ly increases continuously, and the scour width Lx reaches a maximum of 6D when it is 0.5.

In general, the present invention sets up anchor-damage prevention piles 2 around the submarine cable 1 to be protected of the wind turbine 11, and it must be ensured that the submarine cable 1 to be protected is not affected by excessive scouring and can maintain stability. In the case of setting up in the front and rear along the direction of water flow, it is necessary to ensure that the scouring between the two anchor-damage prevention piles 2 is very small, at least when the spacing ratio is greater than 10, there will be no scouring depth in the middle of the anchor-damage prevention piles 2. After exceeding 10D, the scouring depth of the front anchor-damage prevention pile 2 and the rear anchor-damage prevention pile 2 is also continuously decreasing, and both reach the minimum at 15D. The same row is set perpendicular to the direction of water flow, so that the scouring width Lx cannot touch the submarine cable 1 to be protected, and reaches the maximum of 5D at 0.5D. Combined with the scouring depth, the scouring depth is the smallest after exceeding 10D, and the scouring depth between the two anchor-damage prevention piles 2 also disappears.

Considering that when the anchor is pulled to the cable, the longer the cable is, the shorter the distance the anchor-damage prevention pile 2 moves in the mud, which is less conducive to restricting the movement of the ship. Therefore, the spacing between the anchor-damage prevention piles 2 along the water flow direction is preferably 15D, and the spacing between the anchor-damage prevention piles 2 perpendicular to the water flow direction is preferably 10D.

The present invention reduces the scouring below the submarine cable 1 to be protected by placing an anti-anchor pile 2 on the upstream side of the submarine cable 1 to be protected. The presence of the anti-anchor pile 2 will affect the water flow downstream, the flow velocity will be reduced, and there will be a tail vortex generated by the anti-anchor pile 2; if the distance between the anti-anchor pile 2 and the submarine cable 1 to be protected is reasonably designed, not only can the scouring below the submarine cable 1 to be protected be reduced, but also the silt carried by the tail vortex will fill the scouring hole, so that the depth of the scouring hole of the submarine cable 1 to be protected is reduced or buried.

By installing cylindrical or cubic anchor-damage prevention piles 2, local scouring around the submarine cable 1 to be protected can be reduced under clear water conditions. The size of the anchor-damage prevention piles 2, the spacing (Sp) between the anchor-damage prevention piles 2, and the distance (Xp) between the submarine cable 1 to be protected and the anchor-damage prevention piles 2 are effective variables for reducing scouring around the submarine cable 1 to be protected. The above existing literature points out that, with other variables being the same, the scouring reduction effect of the cubic anchor-damage prevention piles 2 is better than that of the cylindrical anchor-damage prevention piles 2, and Xp=40d is the optimal distance for installing the two groups of anchor-damage prevention piles (d is the diameter of the submarine cable 1 to be protected). This distance can allow the silt washed out of the front anchor-damage prevention piles 2 to cover the submarine cable 1 to be protected, filling the scouring pit.

Therefore, the present invention not only designs the installation position of the anti-anchor pile 2, but also determines the size of the anti-anchor pile 2. The size of the anti-anchor pile 2 determines the size of the ability to restrict the movement of the ship. The larger the anti-anchor pile 2 is, the greater the force required to hook it to move; but if the designed anti-anchor pile 2 is too large, it is not only not conducive to placement and installation and subsequent replacement, but also conflicts with the above-determined spacing.

Most of the submarine cables 1 to be protected have a diameter of 30-40 cm. In order to allow the mud and sand washed out of the front anti-anchor pile 2 to cover the submarine cable 1 to be protected, the distance between the two should be 40d; the anti-anchor device should be installed on both sides of the submarine cable 1 to be protected, that is, the spacing between the anti-anchor piles 2 along the direction of water flow is 80d, and the actual spacing is between 24-32 meters. At the same time, considering that the spacing between the anti-anchor piles 2 along the direction of water flow is preferably 15D, the length of most anti-anchor piles 2 is designed to be 2 meters to achieve an ideal situation.

According to the above existing documents, the design principle of the present invention is obtained: the existence of the anti-anchor pile 2 will change the original flow field state, causing changes in the flow around the to-be-protected submarine cable 1 and the anti-anchor pile 2. For the arrangement of the anti-anchor pile 2, the scouring around the anti-anchor pile 2 must first be considered. In order to make the anti-anchor pile 2 more stable, the scouring around it should be minimized; secondly, the impact of the installation of the anti-anchor pile 2 on the to-be-protected submarine cable 1 must be considered. The existence of the anti-anchor pile 2 may aggravate the scouring near the to-be-protected submarine cable 1, resulting in more serious damage to the bending movement of the to-be-protected submarine cable 1. Considering the above two points, it is critical to reasonably arrange the position of the anti-anchor pile 2.

Layout position: The spacing between the anti-anchor piles 2 along the water flow direction is 15D, and the spacing between the anti-anchor piles 2 perpendicular to the water flow direction is 10D (D is the diameter of the pile, which is equivalent to the side length L of the anti-anchor pile 2 in the present invention), which is 2m here. This side length is suitable for most situations.

Embodiment 1:

1-6, a method for preventing anchor damage of a submarine cable at a mud-entering end according to an embodiment of the present invention comprises the following steps:

S1. Determine the side length L of the anchor damage prevention pile 2 according to the diameter d of the submarine cable 1 to be protected;

S2, a plurality of anchor damage prevention piles 2 are arranged opposite to each other on both sides of the submarine cable 1 to be protected;

S3, according to the side length L of the anti-anchor damage pile 2, determine the spacing Lx between the anti-anchor damage piles 2 perpendicular to the water flow direction and the spacing Ly between the anti-anchor damage piles 2 along the water flow direction;

S4. Adjust the positions of a plurality of anti-anchoring piles 2 according to the spacing Lx between the anti-anchoring piles 2 perpendicular to the water flow direction and the spacing Ly between the anti-anchoring piles 2 along the water flow direction.

The present invention sets obstacles on both sides of the submarine cable through the above-mentioned anchor damage prevention method for the submarine cable at the mud-entering end, blocks the anchor in advance before it approaches the submarine cable, thereby preventing the submarine cable from being hooked. At the same time, considering the influence of the anchor damage prevention piles on the flow field, the spacing of the anchor damage prevention piles is reasonably set to minimize the adverse effect of the anchor damage prevention piles, and at the same time, it can effectively reduce the scouring of mud and sand around the submarine cable, which can effectively protect the submarine cable from damage by the anchor for a long time, while taking into account the cost and construction process.

1-6, in some embodiments of the present invention, in said S1, the formula for determining the side length L of the anti-anchoring pile 2, the spacing Lx between the anti-anchoring piles 2 perpendicular to the water flow direction, and the spacing Ly between the anti-anchoring piles 2 along the water flow direction is:

Lx＝10L

Ly＝15L

1-6, in some embodiments of the present invention, before step S1, step S0 is further included, determining a reference range of submarine cable diameter according to the resistance encountered by the anti-anchor pile 2 when being hooked in the mud, and judging whether the diameter d of the submarine cable 1 to be protected is within the range;

If the diameter of the submarine cable 1 to be protected is too small, take the minimum value in the reference range of the submarine cable diameter for subsequent steps; if the diameter of the submarine cable 1 to be protected is too large, take the maximum value in the reference range of the submarine cable diameter for subsequent steps.

Referring to the figure, in some embodiments of the present invention, in the step S0, the formula according to which the anti-anchor pile 2 is subjected to resistance when being hooked in the mud is:

Where C refers to the resistance coefficient in the sediment, ρ is the sediment density, v is the movement speed, and s is the cross-sectional area of the anti-anchor pile 2.

Considering the situation that the diameter of the submarine cable 1 to be protected is too small or too large, resulting in the side length of the piles being too small or the spacing being too large, an effective range must be determined.

Most of the ships around the wind turbine are maintenance and inspection ships, which are usually small in size and weigh 50-200 tons. At this time, most of the ships are moving with the ocean current or slowly moving. Using the kinetic energy theorem F=ma, m is the mass of the ship, a is the acceleration, and according to the time t when the initial speed of the ship becomes 0, we can get an approximate acceleration value (a=v/t). The force generated by the hook to the device is calculated to be between 10000N and 50000N. According to the formula of the resistance F of the device being hooked in the mud:

Where C refers to the resistance coefficient in the sediment, ρ is the density of the sediment, v is the movement speed, and s is the cross-sectional area of the anti-anchor pile 2;

According to the cross-sectional area of the anti-anchor damage pile 2, the side length L of the anti-anchor damage pile 2 is in the range of 1.5m-4m, and the reference range of the submarine cable diameter is between 0.3-0.75m. The placement parameters of the submarine cable 1 to be protected within this range can be directly calculated using the above formula, and the diameters of most submarine cables 1 to be protected are also within this range. If the diameter of the submarine cable 1 to be protected is too small, the minimum value in the reference range of the diameter of the submarine cable 1 to be protected is taken for subsequent steps. If the diameter of the submarine cable 1 to be protected is too large, the maximum value in the reference range of the diameter of the submarine cable 1 to be protected is taken for subsequent steps.

Embodiment 2:

Referring to Figures 1 and 7-9, a device for preventing anchor damage to a submarine cable at the mud end according to another embodiment of the present invention comprises the above-mentioned anti-anchor damage pile 1, wherein adjacent anti-anchor damage piles 1 arranged perpendicular to the water flow direction are connected by a connecting rope 10, a containing cavity 7 for placing materials is provided in the anti-anchor damage pile 1, and a plurality of resistance-enhancing components 9 are provided on the side walls of the anti-anchor damage pile 1.

7-9 , in some embodiments of the present invention, the anti-anchoring pile 1 is provided with a plurality of connecting columns 8 , and the connecting rope 10 is connected to the anti-anchoring pile 1 via the connecting columns 8 .

7-9 , in some embodiments of the present invention, the anti-anchor pile 1 includes a pile body 3 and a pile cover 5 , the pile cover 5 is connected to the pile body 3 , and the accommodating cavity 7 is disposed in the pile body 3 .

7-9 , in some embodiments of the present invention, a plurality of drainage holes 4 are provided at the bottom of the pile body 3 , and a plurality of exhaust holes 6 are provided on the pile cover 5 .

A large number of stones are placed in the anchor pile 2 as a counterweight, and then placed in the sea at a designed position, arranged on both sides of the submarine cable 1 to be protected. When the anchor sinks to the seabed and moves, it will first hook the connecting rope 10 when it approaches the submarine cable 1 to be protected, causing the anchor pile 2 to move accordingly. However, the huge weight of the anchor pile 2 and the surrounding structure will exert greater resistance in the seabed, which will prevent the anchor from moving further, and at the same time remind the crew to respond in time when they are too close to the submarine cable. The connecting rope 10 is a steel cable.

The anchor-damage-proof pile 2 is a cubic structure, with several resistance-enhancing components 9 arranged on the four sides to increase the resistance encountered when moving in the mud and sand. The resistance-enhancing components 9 are similar in shape to ship anchors. The upper part is a removable pile cover 4, which is provided with several exhaust holes 6. The pile cover 4 is connected to the pile body 3 by bolts. The purpose of the exhaust holes 6 is to facilitate the discharge of internal gas when the device is placed underwater and reduce buoyancy. Several drainage holes 4 are also designed on the bottom surface of the pile body 3, so that the internal moisture can be automatically discharged when the pile is pulled out to the sea to replace stones or repair. Four connecting columns 8 are arranged on the opposite sides of the surrounding area for the connection rope 10 to pass through.

Claims (10)

1. The utility model provides a go into mud end sea cable and prevent anchor pest device, its characterized in that, including waiting to protect a plurality of anchor pest stake of preventing that sea cable both sides set up relatively, connect through connecting the rope between the adjacent anchor pest stake device that prevents that perpendicular to water flow direction set up, be equipped with in the anchor pest stake of preventing and be used for placing the holding chamber of material, the lateral wall of anchor pest stake of preventing is equipped with a plurality of increases and hinders the piece.

2. The mud-end sea cable anchoring damage prevention device according to claim 1, wherein a plurality of connecting columns are arranged on the anchoring damage prevention piles, and the connecting ropes are connected with the anchoring damage prevention piles through the connecting columns.

3. The mud-end sea cable anchoring prevention device according to claim 1, wherein the anchoring prevention pile comprises a pile body and a pile cover, the pile cover is connected with the pile body, and the accommodating cavity is arranged in the pile body.

4. The mud-end sea cable anchoring prevention device according to claim 3, wherein the bottom of the pile body is provided with a plurality of drain holes, and the pile cover is provided with a plurality of exhaust holes.

5. The method for preventing the submarine cable at the mud inlet end from being anchored is characterized by comprising the following steps of:

S1, determining the side length L of the anchor damage prevention pile according to the diameter d of a submarine cable to be protected, wherein the side length L is defined in any one of claims 1-4;

S2, arranging a plurality of anchor damage prevention piles on two sides of the submarine cable to be protected;

s3, determining a distance Lx between the anchor prevention piles in the vertical water flow direction and a distance Ly between the anchor prevention piles in the water flow direction according to the side length L of the anchor prevention piles;

s4, adjusting the positions of a plurality of anchor prevention piles according to the distance Lx between the anchor prevention piles perpendicular to the water flow direction and the distance Ly between the anchor prevention piles along the water flow direction.

6. The method for preventing anchor damage to a mud-end submarine cable according to claim 5, wherein in S1, the formula for determining the side length L of the anchor damage preventing pile is:

7. The method for preventing anchor damage to a mud-end submarine cable according to claim 5, wherein in S3, the formula for determining the distance Lx between the anchor damage preventing piles in the vertical water flow direction is:

Lx＝10L。

8. The method for preventing anchor damage of a mud-side submarine cable according to claim 5, wherein in S3, the formula for determining the spacing Ly between the joint defense anchor damage piles is as follows:

Ly＝15L。

9. The method for preventing anchor damage to a sea cable at a mud end according to claim 7, wherein the step S1 further comprises determining a sea cable diameter reference range according to resistance of the anchor damage preventing pile in sediment caused by movement of a hook, and judging whether the diameter d of the sea cable to be protected is within the range;

if the diameter of the submarine cable to be protected is too small, taking the minimum value in the submarine cable diameter reference range for subsequent steps; if the diameter of the submarine cable to be protected is too large, taking the maximum value in the submarine cable diameter reference range for carrying out the subsequent steps.

10. The method for preventing anchor damage of a mud-side submarine cable according to claim 9, wherein the resistance formula of the anchor damage preventing pile in sediment by the hooked movement is:

Wherein C refers to the resistance coefficient in sediment, ρ is the sediment density, v is the movement speed, and s is the cross-sectional area of the anchor damage prevention pile;

and obtaining the sea cable diameter reference range according to the cross section area of the anchor damage prevention pile.