CN109140047B

CN109140047B - Submarine pipeline for reducing influence of wave action in sandy soil seabed

Info

Publication number: CN109140047B
Application number: CN201811035969.7A
Authority: CN
Inventors: 黄挺; 田英辉; 侯利军; 翟厚明; 白顺亚
Original assignee: Hohai University HHU
Current assignee: Jiangsu jiaoshui construction intelligent equipment Research Institute Co.,Ltd.
Priority date: 2018-09-06
Filing date: 2018-09-06
Publication date: 2020-07-17
Anticipated expiration: 2038-09-06
Also published as: CN109140047A

Abstract

The invention discloses a submarine pipeline for reducing the influence of wave action in a sandy soil seabed, wherein a permeable shell is arranged outside the pipeline, a plurality of anchoring parts are uniformly distributed on the permeable shell, a pressure part is connected above the anchoring parts, the top of the pressure part penetrates through a vertical rod and is connected with a buoyancy ring through a clamping rod, and pore water of a seabed soil body at the periphery of the permeable shell is sucked into the pressure part through a permeable layer and an inner drainage channel in the anchoring parts and is discharged out of the pressure part through a side drainage channel of the pressure part. The two sides of the anchoring part are provided with screw rods which are pressed in a rotating way, and the buoyancy ring can be detached through the clamping rod. According to the invention, the buoyancy ring is driven by waves to move up and down to generate vacuum negative pressure, so that the pore water of the seabed soil body is promoted to be discharged, the weakening influence of the pore water pressure accumulation on the bearing capacity of the soil body is reduced, and no additional device is needed for providing energy during working; the anchoring part can provide the self gravity pressure stabilization effect and also can provide the anchoring pressure of anchor rods on two sides, and the screw penetrates through the easily liquefied layer, so that the capability of the pipeline for resisting the liquefaction of the seabed is enhanced.

Description

Submarine pipeline for reducing influence of wave action in sandy soil seabed

Technical Field

The invention relates to the field of ocean structure foundation engineering, and relates to disaster response control of a submarine pipeline under the action of waves in a sandy seabed.

Background

With economic development and further expansion of production scale, offshore oil and gas production becomes an important energy source at present. However, the marine environment is complex and variable, and besides a lot of challenges are brought to the mining operation, pipeline transportation of oil and gas also has a lot of problems. For example, the wave pressure generated by the violent wave action may act on the surface of the seabed, and for a sandy seabed with low permeability, the pore water pressure may be accumulated in the seabed, and even liquefaction occurs. With the rising of the pore water pressure, the bearing capacity of the seabed soil body is gradually weakened and even completely lost (liquefied). When the seabed soil body can not provide enough bearing capacity to resist pipeline load, the pipeline will displace, and then deformation stress is generated, and pipeline structure is damaged in serious cases. An oil and gas pipeline positioned in a marine environment is almost inevitably subjected to strong wave action during the engineering use period, and how to ensure that the pipeline is stable and does not displace and deform under the environment is an important subject related to the normal development of offshore oil and gas engineering.

In the existing engineering, in order to improve the stability of the submarine pipeline under the action of waves, the modes of increasing the buried depth, treating the foundation and the like are generally adopted. Although the above methods have certain effects, they have different disadvantages. For example, the pipeline can be buried below a possible liquefaction depth by increasing the pipeline burying depth, so that the influence of the pressure of the wave pore water is avoided, but the trench wall needs to be set to a slope for stabilization, the engineering quantity of digging and filling soil is greatly increased, and the corresponding pipeline engineering cost is greatly increased. The foundation treatment is a conventional method for solving the bearing capacity problem of a soft foundation, and adopts foundation treatment measures such as grouting on the soil body around a submarine pipeline, and avoids the increase of pore water pressure by changing soil property and isolating pore water flow. But the curing agent needs consolidation time, has slow effect, changes the original components of the seabed, and has great influence on the seabed environment.

In order to solve the problem of stability of the submarine pipeline under the action of strong waves, the method has important significance in developing a pipeline with more anchoring force in a targeted manner.

Disclosure of Invention

The invention provides a novel pipeline form for solving the problem of stability of an oil-gas pipeline caused by the weakening of a sandy seabed soil body under the action of waves, and the problem can be solved by utilizing water particle motion generated by the action of waves to drive a buoyancy ring to move up and down, so that the effect of sucking out pore water of the soil body at the periphery of the pipeline is generated, the pore water pressure is prevented from being accumulated at the periphery of the pipeline, and the effect of controlling the stability of the pipeline structure under the action of waves is achieved.

The technical problem to be solved by the invention is realized by the following technical scheme:

a submarine pipeline for reducing the influence of wave action in sandy soil seabed comprises a pipeline, wherein a permeable shell is sleeved outside the pipeline, a plurality of permeable holes are uniformly formed in the permeable shell, a plurality of anchoring parts are uniformly arranged outside the permeable shell, a gap matched with the permeable shell is formed in the lower part of each anchoring part, the permeable shell is arranged in the gap of each anchoring part in a penetrating manner, a pressure part is arranged at the top of each anchoring part, the pressure part is of a hollow cylinder structure and comprises a hollow part and a solid part, the central axis of the pressure part is perpendicular to the central axis of the pipeline, a vertical rod is arranged in the hollow part in the pressure part in a sliding manner, one end of the vertical rod is positioned in the pressure part, the other end of the vertical rod extends out of the pressure part, a pressing plate is arranged at the end part of the vertical rod positioned in the pressure part, the pressing plate is parallel to the bottom of the pressure part, the convex ring is clamped with a clamping rod, a buoyancy ring is sleeved on the clamping rod, and the clamping rod and the vertical rod are on the same vertical line;

the anchoring part is internally provided with a plurality of internal drainage channels, one end of each internal drainage channel is communicated with the permeation shell, the other end of each internal drainage channel is communicated with the hollow part of the pressure part from the bottom of the pressure part, the bottom of the hollow part is provided with an internal drainage valve capable of closing the internal drainage channel, the solid part in the pressure part is provided with a plurality of side drainage channels, one end of each side drainage channel is communicated with the hollow part of the pressure part, the other end of each side drainage channel is led to the outside of the pressure part, and a channel port of each side drainage channel led to the outside is provided with a side drainage valve capable of closing the side drainage channel.

Furthermore, a permeable layer for limiting seabed sediment from entering the inner drainage channel is filled between the pipeline and the permeable shell.

Further, the screw rod is all worn to be equipped with in the both sides that lie in the pipeline on the anchoring portion, the screw rod can be in the rotatory lift in the anchoring portion, the screw rod is on a parallel with the pole setting, the end that the pole setting was kept away from to the screw rod stretches out anchoring portion, the screw rod cap is installed to the screw rod other end.

Furthermore, the bottom of the pressure part is provided with a limiting ring used for limiting the pressure plate to contact the inner drainage valve.

Furthermore, the top of the pressure part is provided with a through hole.

Furthermore, a hollow central ring is installed in the buoyancy ring, the clamping rods penetrate through the central ring, each clamping rod comprises two clamping rod shafts which are arranged in a crossed mode, the clamping rod shafts can rotate around the crossed position relatively, and springs are clamped at the end portions, far away from the vertical rod, of the two clamping rod shafts.

Further, the diameter of the notch of the anchoring portion is equal to the outer diameter of the infiltration housing.

Further, the pressing plate is of a circular structure, and the diameter of the pressing plate is equal to the inner diameter of the pressure part.

Furthermore, the side drain valve and the inner drain valve are both one-way valves, the side drain valve is only opened to the outside of the pressure part, water in the pressure part is discharged outwards, the inner drain valve is only opened to the inside of the pressure part, and water in the anchoring part is discharged into the pressure part.

The invention has the beneficial effects that:

1. by arranging a drainage path between seabed soil around the pipeline and the pressure part and utilizing the vacuum negative pressure formed at the pressure part, pore water of the soil around the pipeline is sucked out through the pipeline structure. Due to the fact that the water head difference and the smoothness of drainage are increased, compared with a conventional pipeline structure, the phenomenon that pore water is accumulated under the action of waves generated by soil around the pipeline structure is not prone to occurring, and the pipeline structure is prevented from being damaged.

2. The outer side of the permeation shell is provided with the anchoring part, so that the pressure stabilization effect on the pipeline can be realized by utilizing the self weight, more anchoring force than that of the common pipeline can be provided by rotationally pressing the screw rods into the two sides, and the anchoring force of the soil body below the easy-to-liquefy layer can be ensured even if the liquefaction phenomenon occurs because the length of the anchor rod can reach the position below the easy-to-liquefy layer, so that the structural stability of the invention is ensured.

3. The process of generating pore water suction force does not need additional energy supply, the buoyancy ring can be quickly connected and fixed to the top end of the upright stanchion by conveniently designing and installing the buoyancy ring, the buoyancy ring is driven to move up and down by waves, and vacuum negative pressure for providing suction force is generated at the pressure part.

Drawings

FIG. 1 is a schematic view of the overall structure of the apparatus of the present invention;

FIG. 2 is a schematic view of the structure of section A-A in FIG. 1;

FIG. 3 is a schematic view of the structure of section B-B in FIG. 1;

fig. 4 is an enlarged schematic view of portion I of fig. 3.

Description of reference numerals:

1-clamping rod, 2-central ring, 3-buoyancy ring, 4-vertical rod, 5-pressure part, 6-screw cap, 7-permeation hole, 8-permeation shell, 9-anchoring part, 10-screw, 11-spring, 12-permeation layer, 13-clamping rod shaft, 14-vertical rod, 15-through hole, 16-pressing plate, 17-side water discharge valve, 18-side water discharge channel, 19-inner water discharge valve, 20-limiting ring, 21-inner water discharge channel and 22-pipeline.

Detailed Description

The present invention is further illustrated by the following specific examples, which are intended to be illustrative, not limiting and are not intended to limit the scope of the invention.

As shown in fig. 1 to 4, a submarine pipeline for reducing the influence of wave action in sand and soil seabed comprises a pipeline 22, a permeable shell 8 is sleeved outside the pipeline 22, the permeable shell 8 is a high-strength steel shell, and the specific strength value is determined by the actual working condition. A plurality of permeation holes 7 are uniformly arranged on the permeation shell 8. The permeable layer 12 is also filled between the pipe 22 and the permeable casing 8, and the permeable layer can fix the permeable casing 8. Permeable layer 12 is formed of a highly permeable material, and the pore size of the pores of permeable layer 12 is smaller than the pore size of the seabed soil particles. A plurality of anchoring parts 9 are evenly installed outside the permeable casing 8, the anchoring parts 9 are in the shape of a steel rectangle block, the lower part of the anchoring parts 9 is provided with a notch matched with the permeable casing 8, the notch is a semicircular notch, the permeable casing 8 is arranged in the notch of the anchoring parts 9 in a penetrating manner, and the diameter of the notch of the anchoring parts 9 is equal to the outer diameter of the permeable casing 8. The anchoring portion 9 is provided with threaded rods 10 on both sides of the pipeline 22, and the threaded rods 10 can rotatably move in the anchoring portion 9 to extend into the seabed below. The screw 10 is perpendicular to the pipe 22, the lower part of the screw 10 extends out of the anchoring part 9, the upper part of the screw 10 extends out of the anchoring part 9, and the upper part of the screw 10 is provided with a prismatic screw cap 6 for applying the rotating pressure. The screw 10 is externally threaded and bottom-toothed to facilitate penetration into the seabed and provide more anchoring force.

The top welding of anchor portion 9 has pressure portion 5, and pressure portion 5 is hollow cylinder structure, and pressure portion 5 includes hollow portion and solid portion. The hollow part of the pressure part 5 is also of a cylindrical structure, and the central axis of the hollow part and the central axis of the pressure part 5 are on the same straight line. The central axis of the pressure part 5 is perpendicular to the central axis of the pipe 22. The hollow part in pressure portion 5 slides and is provided with pole setting 4, and pole setting 4 is the steel round bar, and pole setting 4 one end is in pressure portion 5, and the other end of pole setting 4 stretches out pressure portion 5. The end of the upright 4 in the pressure part 5 is provided with a pressure plate 16, the pressure plate 16 is of a circular structure, and the diameter of the pressure plate 16 is equal to the inner diameter of the pressure part 5. The pressure plate 16 is parallel to the bottom of the pressure part 5, and the upright 4 can be moved with the pressure plate 16 in the pressure part 5.

A plurality of inner drainage channels 21 are formed in the anchoring portion 9, and the permeable layer 12 of the present invention is also used to prevent sediment on the seabed from being directly sucked into the inner drainage channels 21. One end of the inner drainage channel 21 is communicated with the permeable shell 8, the other end of the inner drainage channel 21 is communicated with the hollow part from the bottom of the pressure part 5, and the bottom of the hollow part is provided with an inner drainage valve 19 which can close the inner drainage channel 21. A plurality of side drainage channels 18 are formed in the solid part of the pressure part 5, one end of each side drainage channel 18 is communicated with the hollow part of the pressure part 5, the other end of each side drainage channel 18 is led to the outside of the pressure part 5, and a side drainage valve 17 capable of closing the side drainage channel 18 is installed at a channel port of the side drainage channel 18 led to the outside. The side drain valve 17 and the inner drain valve 19 are both one-way valves, the side drain valve 17 is opened only to the outside of the pressure part 5 and only allows water in the pressure part 5 to be discharged to the outside, and the inner drain valve 19 is opened only to the inside of the pressure part 5 and only allows water in the anchor part 9 to be discharged to the inside of the pressure part 5. The top of the pressure part 5 of the invention is provided with a through hole 15, and the through hole 15 can drain water behind the pressure plate 16 when the upright post 4 sucks the water out of the pressure part 5. The bottom of the pressure part 5 is provided with a limiting ring 20 used for limiting the pressure plate 16 to contact the inner drain valve 19, so that the pressure plate 16 is prevented from pressing the inner drain valve 19 to influence the overall work during work.

The end part of the upright stanchion 4 far away from the pressure part 5 is provided with a convex ring 14, and the convex ring 14 is a semi-circle ring made of steel. Clamping rods 1 are clamped on the convex rings 14, and the clamping rods 1 and the vertical rods 4 are on the same vertical line. The clamping rod 1 comprises two clamping rod shafts 13 which are arranged in a crossed mode, and the clamping rod shafts 13 can rotate around the crossed positions relatively. The clamping rod 1 is sleeved with a buoyancy ring 3, the buoyancy ring 3 is filled with filler, and the overall mass of the buoyancy ring 3 is similar to the seawater density. Install hollow central ring 2 in the buoyancy circle 3, clamping bar 1 wears to establish in central ring 2, and clamping bar axle 13 and the welding of central ring 2 inner wall, the upper end clamp of clamping bar axle 13 far away from bulge loop 14 holds spring 11, spring 11 is used for the upper end of external pressure clamping bar axle 13, and then buoyancy circle 3 steadies in the top of pole setting 4, and when the buoyancy circle 3 was taken out to needs, the upper end of internal pressure clamping bar axle 13 made buoyancy circle 3 and pole setting 4 upper end separation, takes out buoyancy circle 3 again.

The working principle of the invention is as follows:

firstly, the pipeline 22 is integrally placed to a specified seabed position, and then the screw rods 10 on two sides of the anchoring part 9 are rotationally pressed in to stabilize the whole device. When the sea bed soil body pore water pressure response is caused by the violent wave action, the clamping rod 1 is clamped to the convex ring 14 at the top end of the vertical rod 4 in advance, and the buoyancy ring 3 is connected with the vertical rod 4. The wave action drives the buoyancy ring 3 to move up and down, the movement of the buoyancy ring 3 drives the vertical rod 4 to move up and down, and the movement of the vertical rod 4 further drives the pressing plate 16 to move up and down in the pressure part 5. When the pressing plate 16 moves upward, a negative pressure is formed in the pressure part 5, and the internal drainage valve 19 is opened by the negative pressure, so that water permeating the pores in the soil around the outer shell 8 flows into the hollow part of the pressure part 5 through the permeation layer 12 and the internal drainage channel 21. When the pressing plate 16 moves downward, the internal drain valve 19 is closed, and the water in the pressure section 5 is drained through the side drain passage 18 and the side drain valve 17. The pressing plate 16 is driven by waves to circularly and repeatedly move up and down, so that the purpose of reducing the adverse influence of wave action by using wave energy is achieved.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. The utility model provides a reduce submarine pipeline of wave effect influence in sand seabed which characterized in that: including pipeline (22), pipeline (22) overcoat is equipped with infiltration shell (8), a plurality of infiltration hole (7) have evenly been seted up on infiltration shell (8), evenly install a plurality of anchor portion (9) outside infiltration shell (8), the breach that matches infiltration shell (8) is seted up to anchor portion (9) lower part, infiltration shell (8) are worn to establish in the breach of anchor portion (9), pressure portion (5) are installed at the top of anchor portion (9), pressure portion (5) are hollow cylinder structure, pressure portion (5) include hollow portion and solid portion, the center pin of pressure portion (5) is perpendicular to the center pin of pipeline (22), hollow portion slides in pressure portion (5) and is provided with pole setting (4), pole setting (4) one end is in pressure portion (5), pole setting (4) other end stretches out pressure portion (5), a pressing plate (16) is mounted at the end part, located in the pressure part (5), of the vertical rod (4), the pressing plate (16) is parallel to the bottom of the pressure part (5), a convex ring (14) is mounted at the end part, far away from the pressure part (5), of the vertical rod (4), a clamping rod (1) is clamped on the convex ring (14), a buoyancy ring (3) is sleeved on the clamping rod (1), and the clamping rod (1) and the vertical rod (4) are on the same vertical line;

a plurality of inner drainage channels (21) are arranged in the anchoring portion (9), one end of each inner drainage channel (21) is communicated with the permeable shell (8), the other end of each inner drainage channel (21) is communicated with the hollow part of the pressure portion (5) from the bottom of the pressure portion (5), an inner drainage valve (19) of each inner drainage channel (21) which can be closed is installed at the bottom of the hollow part, a plurality of side drainage channels (18) are arranged on the solid part in the pressure portion (5), one end of each side drainage channel (18) is communicated with the hollow part of the pressure portion (5), the other end of each side drainage channel (18) is led to the outside of the pressure portion (5), and a side drainage valve (17) of each side drainage channel (18) which can be closed is installed on a channel opening of each side drainage channel (18) led to the outside.

2. A subsea pipeline for reducing the effects of wave action in a sandy sea bed as claimed in claim 1 wherein: and a permeable layer (12) for limiting seabed sediment from entering the inner drainage channel (21) is filled between the pipeline (22) and the permeable shell (8).

3. A subsea pipeline for reducing the effects of wave action in a sandy sea bed as claimed in claim 2 wherein: screw rod (10) are all worn to be equipped with in the both sides that lie in pipeline (22) on anchoring portion (9), screw rod (10) can rotate in anchoring portion (9) and go up and down, screw rod (10) are on a parallel with pole setting (4), anchoring portion (9) are stretched out to the tip that pole setting (4) were kept away from in screw rod (10), screw rod cap (6) are installed to the screw rod (10) other end.

4. A subsea pipeline for reducing the effects of wave action in a sandy sea bed as claimed in claim 3 wherein: and a limiting ring (20) used for limiting the pressure plate (16) to contact the inner drainage valve (19) is arranged at the bottom of the pressure part (5).

5. A subsea pipeline according to claim 4 for reducing the effects of wave action in a sand seabed, characterized in that: the top of the pressure part (5) is provided with a through hole (15).

6. A subsea pipeline for reducing the effects of wave action in a sandy sea bed as claimed in claim 1 wherein: the floating ring (3) is internally provided with a hollow central ring (2), the clamping rod (1) is arranged in the central ring (2) in a penetrating mode, the clamping rod (1) comprises two clamping rod shafts (13) which are arranged in a crossed mode, the clamping rod shafts (13) can rotate around the crossed position relatively, and springs (11) are clamped at the end portions, far away from the vertical rod (4), of the two clamping rod shafts (13).

7. A subsea pipeline for reducing the effects of wave action in a sandy sea bed as claimed in claim 1 wherein: the diameter of the recess of the anchoring section (9) is equal to the outer diameter of the infiltration housing (8).

8. A subsea pipeline for reducing the effects of wave action in a sandy sea bed as claimed in claim 1 wherein: the pressing plate (16) is of a circular structure, and the diameter of the pressing plate (16) is equal to the inner diameter of the pressure part (5).

9. A subsea pipeline for reducing the effects of wave action in a sandy sea bed as claimed in claim 1 wherein: the side drain valve (17) and the inner drain valve (19) are all one-way valves, the side drain valve (17) is opened only to the outside of the pressure part (5), water in the pressure part (5) is discharged outwards, the inner drain valve (19) is opened only to the inside of the pressure part (5), and water in the anchoring part (9) is discharged into the pressure part (5).